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Prof. Huijun Li
Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, NSW 2522, Australia

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0 High Temperature Materials
0 high strength steel
0 Materials Characterisation
0 nuclear materials
0 High entropy materials

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Journal article
Published: 05 August 2021 in Intermetallics
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Alumina-forming austenitic (AFA) steel with high creep strengths and excellent high-temperature corrosion resistance has a promising potential being applied to high-temperature components of ultra-supercritical power plants. The effect of Cu addition on microstructure and tensile properties of Fe–20Ni–14Cr alumina-forming austenitic (AFA) steel after aging at 973 K has been investigated using various morphology microscopic characterizations and tensile test. The obtained results show that Cu addition promotes the formation of nanoscale B2–NiAl phase in AFA steel, which further increases the tensile strength and ductility of the materials to 1464 MPa and ductility of 23.81%, respectively. By occupying Fe and Ni atoms locations in the nanoscale B2–NiAl phase of AFA steel, Cu atoms reduce the chemical driving force of the nanoscale B2–NiAl phase growth. Such phenomenon results in reduction of the corresponding phase formation energy, and thus improves the phase stability. The occupancy behavior of Cu and its effect on the particle size in nanoscale B2–NiAl phase were quantitatively evaluated by first-principle calculation. The present research work proves that the precipitation strengthening plays a dominant role in the yield strength improvement of AFA steel.

ACS Style

Qiuzhi Gao; Bingyi Lu; Qingshuang Ma; Hailian Zhang; Huijun Li; Ziyun Liu. Effect of Cu addition on microstructure and properties of Fe–20Ni–14Cr alumina-forming austenitic steel. Intermetallics 2021, 138, 107312 .

AMA Style

Qiuzhi Gao, Bingyi Lu, Qingshuang Ma, Hailian Zhang, Huijun Li, Ziyun Liu. Effect of Cu addition on microstructure and properties of Fe–20Ni–14Cr alumina-forming austenitic steel. Intermetallics. 2021; 138 ():107312.

Chicago/Turabian Style

Qiuzhi Gao; Bingyi Lu; Qingshuang Ma; Hailian Zhang; Huijun Li; Ziyun Liu. 2021. "Effect of Cu addition on microstructure and properties of Fe–20Ni–14Cr alumina-forming austenitic steel." Intermetallics 138, no. : 107312.

Journal article
Published: 19 July 2021 in Metals
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Recently developed Ti-alloyed martensitic steels are believed to exhibit higher wear resistance than traditionally quenched and tempered medium carbon steels. However, their properties may deteriorate during thermal cutting and welding as a result of microstructure tempering. This would present significant challenges for the metal fabrication industries. A decrease in strength and wear resistance associated with tempering should vary with steel composition, initial steel microstructure and properties, and cutting method. In this work, we investigated the effect of thermal cutting on the edge microstructure and properties in two alloyed plate steels containing 0.27C-0.40Ti and 0.39C-0.60Ti (wt.%) commercially rolled to 12 mm thickness. Three cutting methods were applied to each of the two plates: oxy-fuel, plasma and water-jet. Microstructure characterisation was carried out using optical and scanning electron microscopy. With an increase in thermal effect, from water-jet to plasma to oxy-fuel, the heat affected zone width increased and hardness decreased in both steels. However, the hardness profile from the cut edge to the base metal significantly varied with steel composition, particularly C and Ti contents. The dependence of grain structure and precipitation kinetics on steel composition, and cutting method, were thoroughly investigated and linked to the hardness profile variation. The obtained results will be used to optimise the technological parameters for cutting and welding of Ti-alloyed martensitic steels.

ACS Style

Andrii Kostryzhev; Muhammad Rizwan; Chris Killmore; Dake Yu; Huijun Li. Edge Microstructure and Strength Gradient in Thermally Cut Ti-Alloyed Martensitic Steels. Metals 2021, 11, 1138 .

AMA Style

Andrii Kostryzhev, Muhammad Rizwan, Chris Killmore, Dake Yu, Huijun Li. Edge Microstructure and Strength Gradient in Thermally Cut Ti-Alloyed Martensitic Steels. Metals. 2021; 11 (7):1138.

Chicago/Turabian Style

Andrii Kostryzhev; Muhammad Rizwan; Chris Killmore; Dake Yu; Huijun Li. 2021. "Edge Microstructure and Strength Gradient in Thermally Cut Ti-Alloyed Martensitic Steels." Metals 11, no. 7: 1138.

Research paper
Published: 19 June 2021 in Welding in the World
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Significant cost and time savings may be realised if multiple weld repairs are undertaken at the same location during the long-term maintenance of naval vessels. Consequently, this investigation simulates full-thickness hull welds, which are required to facilitate the removal and subsequent replacement of hull sections, by assessing the effects of 4 reoccurring weld repairs on a propriety quenched and tempered steel used for naval applications. Optical metallography, electron backscattering diffraction (EBSD), hardness maps, Charpy impact, and dynamic tear tests were conducted. A combination of real weld repairs and Gleeble heat-affected zone (HAZ) simulations were undertaken to characterise the effects of repeated thermal cycles on the microstructure and toughness of different sub-HAZ regions. When the intercritical reheat temperature was just above the AC1 lower critical transformation temperature, the impact toughness was substantially reduced. This includes the fine-grained HAZ where high toughness is typically expected. The low toughness was attributed to the promotion of fracture initiation via debonding between the matrix and second phase which formed at prior austenite grain boundaries. Compared to the original toughness, the application of multiple repeat welds or multiple simulations of the same sub-HAZ thermal cycle did not deteriorate toughness nor noticeably alter the final microstructure.

ACS Style

Kristin R. Carpenter; Pragathi Dissanayaka; Zoran Sterjovski; Huijun Li; Joe Donato; Azdiar A. Gazder; Stephen van Duin; Dan Miller; Mikael Johansson. The effects of multiple repair welds on a quenched and tempered steel for naval vessels. Welding in the World 2021, 1 -16.

AMA Style

Kristin R. Carpenter, Pragathi Dissanayaka, Zoran Sterjovski, Huijun Li, Joe Donato, Azdiar A. Gazder, Stephen van Duin, Dan Miller, Mikael Johansson. The effects of multiple repair welds on a quenched and tempered steel for naval vessels. Welding in the World. 2021; ():1-16.

Chicago/Turabian Style

Kristin R. Carpenter; Pragathi Dissanayaka; Zoran Sterjovski; Huijun Li; Joe Donato; Azdiar A. Gazder; Stephen van Duin; Dan Miller; Mikael Johansson. 2021. "The effects of multiple repair welds on a quenched and tempered steel for naval vessels." Welding in the World , no. : 1-16.

Review article
Published: 04 June 2021 in Journal of Materials Research and Technology
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Two oxide dispersion strengthened (ODS) steels with compositions of 9Cr-ODS (9Cr-ODS) and 9Cr-3Al-ODS (9Cr-ODS-Al) were fabricated by hot isostatic pressing (HIP). The microstructures and precipitates of the ODS samples were characterized by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that the addition of Al could reduce the precipitation of coarse M23C6 and optimized the size of carbides in ODS steels. Furthermore, it was found that the mean size of nanoparticles in 9Cr-ODS-Al is larger than that in 9Cr-ODS due to the formation of large-size Y–Al–O nanoparticles with Al addition. The tensile test results indicated that the addition of Al slightly decreased the strength of ODS steels, but substantially increased the ductility.

ACS Style

Jianjie Wang; Dijun Long; Liming Yu; Yongchang Liu; Huijun Li; Zumin Wang. Influence of Al addition on the microstructure and mechanical properties of Zr-containing 9Cr-ODS steel. Journal of Materials Research and Technology 2021, 13, 1698 -1708.

AMA Style

Jianjie Wang, Dijun Long, Liming Yu, Yongchang Liu, Huijun Li, Zumin Wang. Influence of Al addition on the microstructure and mechanical properties of Zr-containing 9Cr-ODS steel. Journal of Materials Research and Technology. 2021; 13 ():1698-1708.

Chicago/Turabian Style

Jianjie Wang; Dijun Long; Liming Yu; Yongchang Liu; Huijun Li; Zumin Wang. 2021. "Influence of Al addition on the microstructure and mechanical properties of Zr-containing 9Cr-ODS steel." Journal of Materials Research and Technology 13, no. : 1698-1708.

Journal article
Published: 07 May 2021 in Materials Today Communications
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Wire arc additive manufacturing (WAAM) is a promising alternative to laser-powder based additive manufacturing for fabricating large metallic components due to its high productivity and low cost. The high heat input of the arc welding process causes significant thermal stresses resulting in large distortion of the components. Finite element methods are widely used to analysis arc welding and additive manufacturing process, while the commonly used Gaussian or Double ellipsoid volumetric heat source model requires a large number of mesh points suffering from computational expensive and time consuming. This paper describes the well-distributed volumetric heat source model for numerical simulation of wire arc additive manufacturing process on large components. The proposed well-distributed heat source model is insensitive to mesh, showing a significant advantage with respect to the computational time. The simulated temperature history and distribution are verified by comparison with the experimental results from thermocouples and a high-temperature thermal imaging camera.

ACS Style

Donghong Ding; Shimin Zhang; Qinghua Lu; Zengxi Pan; Huijun Li; Kai Wang. The well-distributed volumetric heat source model for numerical simulation of wire arc additive manufacturing process. Materials Today Communications 2021, 27, 102430 .

AMA Style

Donghong Ding, Shimin Zhang, Qinghua Lu, Zengxi Pan, Huijun Li, Kai Wang. The well-distributed volumetric heat source model for numerical simulation of wire arc additive manufacturing process. Materials Today Communications. 2021; 27 ():102430.

Chicago/Turabian Style

Donghong Ding; Shimin Zhang; Qinghua Lu; Zengxi Pan; Huijun Li; Kai Wang. 2021. "The well-distributed volumetric heat source model for numerical simulation of wire arc additive manufacturing process." Materials Today Communications 27, no. : 102430.

Journal article
Published: 22 March 2021 in Materials
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As promising technology with low requirements and high depositing efficiency, Wire Arc Additive Manufacturing (WAAM) can significantly reduce the repair cost and improve the formation quality of molds. To further improve the accuracy of WAAM in repairing molds, the point cloud model that expresses the spatial distribution and surface characteristics of the mold is proposed. Since the mold has a large size, it is necessary to be scanned multiple times, resulting in multiple point cloud models. The point cloud registration, such as the Iterative Closest Point (ICP) algorithm, then plays the role of merging multiple point cloud models to reconstruct a complete data model. However, using the ICP algorithm to merge large point clouds with a low-overlap area is inefficient, time-consuming, and unsatisfactory. Therefore, this paper provides the improved Offset Iterative Closest Point (OICP) algorithm, which is an online fast registration algorithm suitable for intelligent WAAM mold repair technology. The practicality and reliability of the algorithm are illustrated by the comparison results with the standard ICP algorithm and the three-coordinate measuring instrument in the Experimental Setup Section. The results are that the OICP algorithm is feasible for registrations with low overlap rates. For an overlap rate lower than 60% in our experiments, the traditional ICP algorithm failed, while the Root Mean Square (RMS) error reached 0.1 mm, and the rotation error was within 0.5 degrees, indicating the improvement of the proposed OICP algorithm.

ACS Style

Ruibing Wu; Ziping Yu; Donghong Ding; Qinghua Lu; Zengxi Pan; Huijun Li. OICP: An Online Fast Registration Algorithm Based on Rigid Translation Applied to Wire Arc Additive Manufacturing of Mold Repair. Materials 2021, 14, 1563 .

AMA Style

Ruibing Wu, Ziping Yu, Donghong Ding, Qinghua Lu, Zengxi Pan, Huijun Li. OICP: An Online Fast Registration Algorithm Based on Rigid Translation Applied to Wire Arc Additive Manufacturing of Mold Repair. Materials. 2021; 14 (6):1563.

Chicago/Turabian Style

Ruibing Wu; Ziping Yu; Donghong Ding; Qinghua Lu; Zengxi Pan; Huijun Li. 2021. "OICP: An Online Fast Registration Algorithm Based on Rigid Translation Applied to Wire Arc Additive Manufacturing of Mold Repair." Materials 14, no. 6: 1563.

Journal article
Published: 02 December 2020 in Intermetallics
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Functionally graded material has been increasingly attractive due to the locally designed and optimized material properties. In the present paper, to achieve high thermal lattice structural stability and high corrosion resistance in each side of one bulk material, an Fe3Ni–FeNi compositionally graded material (FGM) bulk sample has been fabricated using an innovative wire-arc additive manufacturing process. A subsequent homogenization post-production heat treatment is applied to stabilize the phase composition and eliminate the possible segregation in the as-fabricated sample. Meanwhile, the high intensity neutron diffraction instrument WOMBAT is conducted to measure the phase evolution processes in the bulk sample in-situ, thus the thermal induced lattice evolutions of Fe3Ni and FeNi can be accurately obtained dynamically in the function of time. According to the results, the WAAM has successfully fabricated the target FGM with uniform Ni content gradient. However, hot cracking defects are found in the bulk sample because of the inadequate interpass temperature setting. As analyzed from neutron diffraction results, the homogenization heat treatment has improved the phase thermal stability of the FGM and the application temperature of the Fe3Ni–FeNi FGM should be limited under 630 °C.

ACS Style

Chen Shen; Klaus-Dieter Liss; Mark Reid; Zengxi Pan; Xueming Hua; Fang Li; Gang Mou; Ye Huang; Bosheng Dong; Dongzhi Luo; Huijun Li. Effect of the post-production heat treatment on phase evolution in the Fe3Ni–FeNi functionally graded material: An in-situ neutron diffraction study. Intermetallics 2020, 129, 107032 .

AMA Style

Chen Shen, Klaus-Dieter Liss, Mark Reid, Zengxi Pan, Xueming Hua, Fang Li, Gang Mou, Ye Huang, Bosheng Dong, Dongzhi Luo, Huijun Li. Effect of the post-production heat treatment on phase evolution in the Fe3Ni–FeNi functionally graded material: An in-situ neutron diffraction study. Intermetallics. 2020; 129 ():107032.

Chicago/Turabian Style

Chen Shen; Klaus-Dieter Liss; Mark Reid; Zengxi Pan; Xueming Hua; Fang Li; Gang Mou; Ye Huang; Bosheng Dong; Dongzhi Luo; Huijun Li. 2020. "Effect of the post-production heat treatment on phase evolution in the Fe3Ni–FeNi functionally graded material: An in-situ neutron diffraction study." Intermetallics 129, no. : 107032.

Journal article
Published: 03 September 2020 in Materials Science and Engineering: A
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The microstructure evolution and creep behavior of aged 2.5Al alumina-forming austenitic (AFA) steel were investigated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle size, volume fraction of precipitates and dislocation density were statistically measured to evaluate the contribution of precipitation strengthening and dislocation strengthening to the creep strength. The results suggested that the phase boundaries between Laves and B2–NiAl were incoherent interface, and both B2–NiAl and Laves are main strengthened phases in aged 2.5Al-AFA steel. In addition, the creep results indicated that the sample aged for 1000 h exhibited creep capability with the smallest creep strain and steady-state creep rate. Our work proved that the isothermal aging is an effective way to improve the creep strength of 2.5Al-AFA steel.

ACS Style

Jundong Jiang; Ziyun Liu; Qiuzhi Gao; Hailian Zhang; Aimin Hao; Fu Qu; Xiaoping Lin; Huijun Li. The effect of isothermal aging on creep behavior of modified 2.5Al alumina-forming austenitic steel. Materials Science and Engineering: A 2020, 797, 140219 .

AMA Style

Jundong Jiang, Ziyun Liu, Qiuzhi Gao, Hailian Zhang, Aimin Hao, Fu Qu, Xiaoping Lin, Huijun Li. The effect of isothermal aging on creep behavior of modified 2.5Al alumina-forming austenitic steel. Materials Science and Engineering: A. 2020; 797 ():140219.

Chicago/Turabian Style

Jundong Jiang; Ziyun Liu; Qiuzhi Gao; Hailian Zhang; Aimin Hao; Fu Qu; Xiaoping Lin; Huijun Li. 2020. "The effect of isothermal aging on creep behavior of modified 2.5Al alumina-forming austenitic steel." Materials Science and Engineering: A 797, no. : 140219.

Journal article
Published: 28 July 2020 in Journal of Manufacturing Processes
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FeNi intermetallic has been continuously attractive due to the appreciable magneto-crystalline anisotropy and high saturation magnetization in the nominally-equiatomic chemically ordered L10 structure. In the present research, the bulk FeNi alloy is successfully fabricated using an innovative wire-arca additive manufacturing process, which is also an in-situ alloying method. In the meantime, to characterize the thermal lattice evolution of the FeNi, neutron diffraction is conducted to the as-fabricated sample in-situ during a heat treatment process. According to the neutron results, an anisotropic fcc-FeNi lattice evolution has been detected, which indicates the existence of FeNi superstructure in the WAAM fabricated FeNi bulk material. In addition, due to the featured advantage of the neutron data, the fcc-FeNi volumetric lattice thermal expansion coefficients during heating and cooling processes are calculated.

ACS Style

Chen Shen; Klaus-Dieter Liss; Mark Reid; Zengxi Pan; Xueming Hua; Fang Li; Gang Mou; Ye Huang; Yanyan Zhu; Huijun Li. Fabrication of FeNi intermetallic using the wire-arc additive manufacturing process: A feasibility and neutron diffraction phase characterization study. Journal of Manufacturing Processes 2020, 57, 691 -699.

AMA Style

Chen Shen, Klaus-Dieter Liss, Mark Reid, Zengxi Pan, Xueming Hua, Fang Li, Gang Mou, Ye Huang, Yanyan Zhu, Huijun Li. Fabrication of FeNi intermetallic using the wire-arc additive manufacturing process: A feasibility and neutron diffraction phase characterization study. Journal of Manufacturing Processes. 2020; 57 ():691-699.

Chicago/Turabian Style

Chen Shen; Klaus-Dieter Liss; Mark Reid; Zengxi Pan; Xueming Hua; Fang Li; Gang Mou; Ye Huang; Yanyan Zhu; Huijun Li. 2020. "Fabrication of FeNi intermetallic using the wire-arc additive manufacturing process: A feasibility and neutron diffraction phase characterization study." Journal of Manufacturing Processes 57, no. : 691-699.

Metals and corrosion
Published: 08 July 2020 in Journal of Materials Science
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Eutectic modification through minor addition of boron was firstly proposed to improve the malleability of brittle eutectic high-entropy alloys (EHEAs). The proposed approach involves adding small amounts of eutectic modifier, boron (0.2–1.6 at.%), to a brittle dual-phase [face centred cubic (FCC) and σ phase] Fe35Ni25Cr25Mo15 EHEA. Here, we report the role of boron additions in improvement of the mechanical properties of a Fe35Ni25Cr25Mo15 EHEA. It was found that with the increase in boron additions up to 1 at.%, the lamellar eutectic structure consisting of FCC and σ intermetallic phase gradually transited to a dendrite-like eutectic structure. As a result, the compressive fracture strain of the alloy was increased about 3 times with a slight reduction in strength. The mechanisms of eutectic morphology transition induced by boron additions in the Fe35Ni25Cr25Mo15 EHEA and their effects on mechanical properties were studied through microstructural characterization and thermodynamic analyses. The transition of eutectic morphology from lamellar eutectic to dendrite eutectic is believed to be resulted from the increased constitutional undercooling caused by B additions. The solute redistribution of B in the liquid ahead of the solid/liquid interface resulted in a B concentration gradient, which led to the formation of a constitutionally undercooled zone at the front of the σ phase, which destabilized the coupled growth conditions necessary for the formation of the lamellar eutectic structure. As a result, the eutectic morphology was transformed from lamellar eutectic to a dendritic-like eutectic structure. This type of structure exhibits a lower fraction of phase boundaries leading to improved malleability of the brittle EHEA. This insight can be used to design new advanced EHEAs through adjustment of the eutectic morphology.

ACS Style

Yu Yin; Qiyang Tan; Tong Wang; Damon Kent; Ning Mo; Michael Bermingham; Huijun Li; Ming-Xing Zhang. Eutectic modification of Fe-enriched high-entropy alloys through minor addition of boron. Journal of Materials Science 2020, 55, 14571 -14587.

AMA Style

Yu Yin, Qiyang Tan, Tong Wang, Damon Kent, Ning Mo, Michael Bermingham, Huijun Li, Ming-Xing Zhang. Eutectic modification of Fe-enriched high-entropy alloys through minor addition of boron. Journal of Materials Science. 2020; 55 (29):14571-14587.

Chicago/Turabian Style

Yu Yin; Qiyang Tan; Tong Wang; Damon Kent; Ning Mo; Michael Bermingham; Huijun Li; Ming-Xing Zhang. 2020. "Eutectic modification of Fe-enriched high-entropy alloys through minor addition of boron." Journal of Materials Science 55, no. 29: 14571-14587.

Journal article
Published: 18 June 2020 in Materials
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Microstructural evolutions of the 4Al alumina-forming austenitic steel after cold rolling with different reductions from 5% to 30% and then annealing were investigated using electron backscattering diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile properties and hardness were also measured. The results show that the average grain size gradually decreases with an increase in the cold-rolling reduction. The low angle grain boundaries (LAGBs) are dominant in the cold-rolled samples, but high angle grain boundaries (HAGBs) form in the annealed samples, indicating that the grains are refined under the action of dislocations. During cold rolling, high-density dislocations are initially introduced in the samples, which contributes to a large number of dislocations remaining after annealing. With the sustaining increase in cold-rolled deformation, the samples exhibit more excellent tensile strength and hardness due to the decrease in grain size and increase in dislocation density, especially for the samples subjected to 30% cold-rolling reduction. The contribution of dislocations on yield strength is more than 60%.

ACS Style

Chenchen Jiang; Qiuzhi Gao; Hailian Zhang; Ziyun Liu; Huijun Li. Microstructure and Mechanical Properties of 4Al Alumina-Forming Austenitic Steel after Cold-Rolling Deformation and Annealing. Materials 2020, 13, 2767 .

AMA Style

Chenchen Jiang, Qiuzhi Gao, Hailian Zhang, Ziyun Liu, Huijun Li. Microstructure and Mechanical Properties of 4Al Alumina-Forming Austenitic Steel after Cold-Rolling Deformation and Annealing. Materials. 2020; 13 (12):2767.

Chicago/Turabian Style

Chenchen Jiang; Qiuzhi Gao; Hailian Zhang; Ziyun Liu; Huijun Li. 2020. "Microstructure and Mechanical Properties of 4Al Alumina-Forming Austenitic Steel after Cold-Rolling Deformation and Annealing." Materials 13, no. 12: 2767.

Journal article
Published: 13 June 2020 in Journal of Alloys and Compounds
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In the present research, to further reduce the fabrication and forming cost of NiTi alloy, an innovative wire-arc additive manufacturing process (WAAM), which is simultaneously an in-situ alloying process, has been applied to fabricate polycrystalline Ni53Ti47. The as-fabricated alloy is subsequently subjected to a necessary post-production annealing for additively manufactured metals. During the thermal cycle, to characterize the obtained phases in the Ni53Ti47 alloy and provide dynamic lattice evolution information, neutron diffraction is conducted to the heated sample in real time. It is found that the metastable Ni4Ti3 phase is only obtained in the heat-treated alloy while the as-fabricated NiTi alloy produced by WAAM contains only NiTi and Ni3Ti. The generated Ni4Ti3 precipitates have increased the NiTi phase micro strains. The hcp-Ni3Ti lattice evolution is found inducing converse lattice shrinkage and expansion in bcc-NiTi lattice during the dissolution and precipitation of Ni3Ti, respectively. The WAAM induced residual stress in the as-fabricated alloy is tensile and during the residual stress relief, the thermal expansion rate of Ni and Ni3Ti are reduced. In addition, the thermal expansion coefficient of NiTi and Ni3Ti is measured according to the neutron Rietveld refinement as 0.040 × 10−3 °C−1 and 0.036 × 10−3 °C−1, respectively.

ACS Style

Chen Shen; Mark Reid; Klaus-Dieter Liss; Xueming Hua; Zengxi Pan; Gang Mou; Ye Huang; Huijun Li. In-situ neutron diffraction study on the high temperature thermal phase evolution of wire-arc additively manufactured Ni53Ti47 binary alloy. Journal of Alloys and Compounds 2020, 843, 156020 .

AMA Style

Chen Shen, Mark Reid, Klaus-Dieter Liss, Xueming Hua, Zengxi Pan, Gang Mou, Ye Huang, Huijun Li. In-situ neutron diffraction study on the high temperature thermal phase evolution of wire-arc additively manufactured Ni53Ti47 binary alloy. Journal of Alloys and Compounds. 2020; 843 ():156020.

Chicago/Turabian Style

Chen Shen; Mark Reid; Klaus-Dieter Liss; Xueming Hua; Zengxi Pan; Gang Mou; Ye Huang; Huijun Li. 2020. "In-situ neutron diffraction study on the high temperature thermal phase evolution of wire-arc additively manufactured Ni53Ti47 binary alloy." Journal of Alloys and Compounds 843, no. : 156020.

Journal article
Published: 10 June 2020 in IEEE Transactions on Instrumentation and Measurement
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A study on the design, framework, experimental arrangement, data acquisition and subsequent analysis of cold crack detection using fiber Bragg grating (FBG) sensors during welding is presented. Cold crack induced acoustic emission (AE) events are detected by multiple FBG sensor configurations and using a commercial FBG AE interrogation system. The crack locations are theoretically predicted using a method of linear localization based on the differences in the time of arrival (ToA) of the AE events at different FBG sensors. The approach is experimentally validated by employing packaged and unpackaged FBG sensor arrays in a welding experiment with gas tungsten arc welding (GTAW) on ultrahigh toughness high hardness armour (UHT HHA) steel. Frequency analysis of the AE events are also carried out to understand the cold crack characteristics. The weld region of the steel plate is diced into 1 mm cross sectional pieces and the positions of the cold cracks are identified using scanning electron microscope (SEM) imaging and then cross correlated with the measured AE events, thereby confirming the correct identification of cold crack location using the FBG sensing method.

ACS Style

Sagar Jinachandran; Yimiao Ning; Bintao Wu; Huijun Li; Jiangtao Xi; B. Gangadhara Prusty; Ginu Rajan. Cold Crack Monitoring and Localization in Welding Using Fiber Bragg Grating Sensors. IEEE Transactions on Instrumentation and Measurement 2020, 69, 9228 -9236.

AMA Style

Sagar Jinachandran, Yimiao Ning, Bintao Wu, Huijun Li, Jiangtao Xi, B. Gangadhara Prusty, Ginu Rajan. Cold Crack Monitoring and Localization in Welding Using Fiber Bragg Grating Sensors. IEEE Transactions on Instrumentation and Measurement. 2020; 69 (11):9228-9236.

Chicago/Turabian Style

Sagar Jinachandran; Yimiao Ning; Bintao Wu; Huijun Li; Jiangtao Xi; B. Gangadhara Prusty; Ginu Rajan. 2020. "Cold Crack Monitoring and Localization in Welding Using Fiber Bragg Grating Sensors." IEEE Transactions on Instrumentation and Measurement 69, no. 11: 9228-9236.

Journal article
Published: 25 February 2020 in Materials Science and Engineering: A
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The effects of the relative content of Al and Ti, and the addition of 2 at.% Cr or Mo to partly substitute Co on the microstructure and mechanical properties of Co–Ni–Al–Ti superalloy were investigated. The microstructures of five as-cast superalloys showed that γ'-(Co,Ni)3(Al,Ti) precipitates segregated on γ-Co matrix and exhibited dendritic morphology. After aging, nano-sized γ'-(Co,Ni)3(Al,Ti) precipitates uniformly precipitated on γ-Co matrix. Ni, Al, Ti and Mo atoms partitioned preferentially to γ′ phase, while Co and Cr atoms partitioned preferentially to γ matrix phase. The increase in Ti content, and the addition of 2 at.% Cr or Mo all increased the volume fraction and the average size of γ′ phase. The lattice misfit increased with the concentration of Ti and the addition of 2 at.% Mo, but decreased with the addition of 2 at.% Cr. With increasing aging time, the size of γ′ phase and lattice misfit increased, while γ′ phase volume fraction increased firstly, and then decreased after reaching the maximum at 100 h. The lattice misfit plays a key role on vicker's hardness in the time of 20 h–100 h aging, while γ′ phase volume fraction plays a decisive role in vicker's hardness after 100 h aging.

ACS Style

Qiuzhi Gao; Yujiao Jiang; Ziyun Liu; Hailian Zhang; Chenchen Jiang; Xin Zhang; Huijun Li. Effects of alloying elements on microstructure and mechanical properties of Co–Ni–Al–Ti superalloy. Materials Science and Engineering: A 2020, 779, 139139 .

AMA Style

Qiuzhi Gao, Yujiao Jiang, Ziyun Liu, Hailian Zhang, Chenchen Jiang, Xin Zhang, Huijun Li. Effects of alloying elements on microstructure and mechanical properties of Co–Ni–Al–Ti superalloy. Materials Science and Engineering: A. 2020; 779 ():139139.

Chicago/Turabian Style

Qiuzhi Gao; Yujiao Jiang; Ziyun Liu; Hailian Zhang; Chenchen Jiang; Xin Zhang; Huijun Li. 2020. "Effects of alloying elements on microstructure and mechanical properties of Co–Ni–Al–Ti superalloy." Materials Science and Engineering: A 779, no. : 139139.

Journal article
Published: 31 January 2020 in Journal of Alloys and Compounds
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In the present research an Fe–Fe3Ni functionally graded material has been fabricated using an innovative wire-arc additive manufacturing process. Considering the residual bcc-α-Fe in the bulk material, a homogenization heat treatment is conducted to the as-fabricated alloy to transform the residual bcc lattice into fcc structure. During the entire heat treatment, the phase evolution process in Fe–Fe3Ni functionally graded material is in-situ characterized using the high-intensity neutron diffraction instrument WOMBAT, therefore the temperature profile is set linear to accurately extract phase volume fractions and thermal lattice strains in the specific regions. According to the results, the as-fabricated functionally graded material contains both fcc-Fe3Ni and bcc-α-Fe, while after heat treatment the bcc-α-Fe is dissolved into the Fe3Ni matrix and leads to lower hardness in the alloy. Also, the detected phase evolutions are mainly performed by the low Ni content section of the Fe–Fe3Ni functionally graded material. In addition, compared to the bcc lattice in the as-fabricated functionally graded material, the dissolved Fe more considerably restraint the Fe3Ni lattice deformation thus a much lower thermal expansion coefficient is measured from cooling than the heating process.

ACS Style

Chen Shen; Xueming Hua; Mark Reid; Klaus-Dieter Liss; Gang Mou; Zengxi Pan; Ye Huang; Huijun Li. Thermal induced phase evolution of Fe–Fe3Ni functionally graded material fabricated using the wire-arc additive manufacturing process: An in-situ neutron diffraction study. Journal of Alloys and Compounds 2020, 826, 154097 .

AMA Style

Chen Shen, Xueming Hua, Mark Reid, Klaus-Dieter Liss, Gang Mou, Zengxi Pan, Ye Huang, Huijun Li. Thermal induced phase evolution of Fe–Fe3Ni functionally graded material fabricated using the wire-arc additive manufacturing process: An in-situ neutron diffraction study. Journal of Alloys and Compounds. 2020; 826 ():154097.

Chicago/Turabian Style

Chen Shen; Xueming Hua; Mark Reid; Klaus-Dieter Liss; Gang Mou; Zengxi Pan; Ye Huang; Huijun Li. 2020. "Thermal induced phase evolution of Fe–Fe3Ni functionally graded material fabricated using the wire-arc additive manufacturing process: An in-situ neutron diffraction study." Journal of Alloys and Compounds 826, no. : 154097.

Journal article
Published: 07 December 2019 in Metals
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Keyhole mode Tungsten Inert Gas (K-TIG) welding is a novel advanced deep penetration welding technology which provides an alternative to high power density welding in terms of achieving keyhole mode welding. In order to facilitate welding procedure optimisation in this newly developed welding technology, the relationship among welding parameters, weld formation and tensile properties during the K-TIG welding was investigated in detail. Results show that except for travel speed, the heat input level also plays an important role in forming undercut defect by changing the plasma jet trajectory inside keyhole channel, leading to the formation of hump in the weld centre and exacerbation of undercut formation. Both undercut defect and root side fusion boundary can act as a stress concentration point, which affects the fracture mode and tensile properties considerably. The research results provide a practical guidance of process parameter optimisation and quality assurance for the K-TIG welding process.

ACS Style

Zhenyu Fei; Zengxi Pan; Dominic Cuiuri; Huijun Li; Bintao Wu; Donghong Ding; Lihong Su. Effect of Heat Input on Weld Formation and Tensile Properties in Keyhole Mode TIG Welding Process. Metals 2019, 9, 1327 .

AMA Style

Zhenyu Fei, Zengxi Pan, Dominic Cuiuri, Huijun Li, Bintao Wu, Donghong Ding, Lihong Su. Effect of Heat Input on Weld Formation and Tensile Properties in Keyhole Mode TIG Welding Process. Metals. 2019; 9 (12):1327.

Chicago/Turabian Style

Zhenyu Fei; Zengxi Pan; Dominic Cuiuri; Huijun Li; Bintao Wu; Donghong Ding; Lihong Su. 2019. "Effect of Heat Input on Weld Formation and Tensile Properties in Keyhole Mode TIG Welding Process." Metals 9, no. 12: 1327.

Journal article
Published: 31 October 2019 in Materials
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The ballistic performance of armour steel welds using austenitic filler materials is poor on account of the disparity in the mechanical properties of the weld and base metals. Consequently, a novel Keyhole Gas Tungsten Arc Welding process with a trapezoidal AISI309 austenitic stainless steel interlayer was developed to tailor chemical composition and microstructure by controlling the solidification sequence. Results show that the dilution rate in the weld metal region can reach up to 43.5% by placing a specially designed interlayer in between the base metal, providing a major scope for microstructure modification. Detailed weld analysis was undertaken by X-ray diffraction, optical and secondary and transmission electron microscopy, energy dispersive spectroscopy and electron back-scattering diffraction. The results from Vickers hardness indents and Charpy impact toughness testing at −40 °C show that the properties of the weld metal region are comparable to that of the base metal. This is ascribed to the weld metal comprising a two phase microstructure of martensite and retained austenite, which contribute to improvements in strength and toughness, respectively. Furthermore, the tailored chemical composition, microstructure and low temperature phase transformation in the weld metal may reduce the tendency toward both solidification cracking and hydrogen assisted cold cracking.

ACS Style

Zhenyu Fei; Zengxi Pan; Dominic Cuiuri; Huijun Li; Azdiar A. Gazder. A Combination of Keyhole GTAW with a Trapezoidal Interlayer: A New Insight into Armour Steel Welding. Materials 2019, 12, 3571 .

AMA Style

Zhenyu Fei, Zengxi Pan, Dominic Cuiuri, Huijun Li, Azdiar A. Gazder. A Combination of Keyhole GTAW with a Trapezoidal Interlayer: A New Insight into Armour Steel Welding. Materials. 2019; 12 (21):3571.

Chicago/Turabian Style

Zhenyu Fei; Zengxi Pan; Dominic Cuiuri; Huijun Li; Azdiar A. Gazder. 2019. "A Combination of Keyhole GTAW with a Trapezoidal Interlayer: A New Insight into Armour Steel Welding." Materials 12, no. 21: 3571.

Journal article
Published: 05 April 2019 in Materials Science and Engineering: A
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Microstructural evolutions during hot deformation and annealing of alumina-forming austenitic (AFA) steel were investigated using electron backscatter diffraction (EBSD). Tensile properties of as-obtained AFA steel were also tested. The yield strength and ultimate tensile stress of deformed AFA steel increase gradually with the increase in rolling reduction, while the fracture elongation decreases rapidly. Specifically, after hot-rolling with the reduction of 40%, the yield strength of the annealed specimen is high to 773.2 MPa, and the fracture elongation of this sample is about 43.6%. The excellent mechanical property can be attributed to the smaller average grain, larger Schmid factor and coincident site lattice (CSL) boundaries. Such a rapid decline of the elongation of AFA steel occurs due to increasing low angle grain boundaries (LAGB, 15°).

ACS Style

Ziyun Liu; Qiuzhi Gao; Hailian Zhang; Shaohua Luo; Xin Zhang; Wang Li; Yujiao Jiang; Huijun Li. EBSD analysis and mechanical properties of alumina-forming austenitic steel during hot deformation and annealing. Materials Science and Engineering: A 2019, 755, 106 -115.

AMA Style

Ziyun Liu, Qiuzhi Gao, Hailian Zhang, Shaohua Luo, Xin Zhang, Wang Li, Yujiao Jiang, Huijun Li. EBSD analysis and mechanical properties of alumina-forming austenitic steel during hot deformation and annealing. Materials Science and Engineering: A. 2019; 755 ():106-115.

Chicago/Turabian Style

Ziyun Liu; Qiuzhi Gao; Hailian Zhang; Shaohua Luo; Xin Zhang; Wang Li; Yujiao Jiang; Huijun Li. 2019. "EBSD analysis and mechanical properties of alumina-forming austenitic steel during hot deformation and annealing." Materials Science and Engineering: A 755, no. : 106-115.

Journal article
Published: 12 March 2019 in Materials Science and Engineering: A
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Two NiCu alloys with various contents of Mn, Ti, Al and C were deposited in a shape of single-bead multi layered walls using wire arc additive manufacturing technology. To modify solute atom concentrations and particle number density values, the as-welded alloys were subjected to annealing at 1100 °C and age-hardening heat treatment in the 610-480 °C temperature range. Microstructure characterisation was carried out using optical, scanning, conventional transmission and atomic resolution transmission electron microscopy. Work hardening behaviour was studied using tensile testing. For similar deposition and heat treatment conditions, an alloy with higher C and Al, and lower Mn contents exhibited a higher number density of >20 nm TiC particles, higher number density of <20 nm γ′-Ni3(Al, Ti) particles, and, associated with these, superior hardness, tensile strength, strain hardening rate and toughness. The comparative effect of solid solution and precipitation strengthening on work hardening behaviour and fracture mode is discussed.

ACS Style

O.O. Marenych; A.G. Kostryzhev; Z. Pan; H. Li; S. van Duin. Comparative effect of Mn/Ti solute atoms and TiC/Ni3(Al,Ti) nano-particles on work hardening behaviour in Ni Cu alloys fabricated by wire arc additive manufacturing. Materials Science and Engineering: A 2019, 753, 262 -275.

AMA Style

O.O. Marenych, A.G. Kostryzhev, Z. Pan, H. Li, S. van Duin. Comparative effect of Mn/Ti solute atoms and TiC/Ni3(Al,Ti) nano-particles on work hardening behaviour in Ni Cu alloys fabricated by wire arc additive manufacturing. Materials Science and Engineering: A. 2019; 753 ():262-275.

Chicago/Turabian Style

O.O. Marenych; A.G. Kostryzhev; Z. Pan; H. Li; S. van Duin. 2019. "Comparative effect of Mn/Ti solute atoms and TiC/Ni3(Al,Ti) nano-particles on work hardening behaviour in Ni Cu alloys fabricated by wire arc additive manufacturing." Materials Science and Engineering: A 753, no. : 262-275.

Metals
Published: 08 March 2019 in Journal of Materials Science
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The flow behavior of alumina-forming austenitic steel was studied using axisymmetric hot compression on a Gleeble-3500 thermomechanical simulator. The temperature range was 900–1200 °C, and strain rate range was 0.1–100 s−1. The microstructures after deformation were investigated by electron backscattering diffraction (EBSD) and transmission electron microscopy (TEM). The deformation temperature and strain rate have a significant influence on the flow stress. A constitutive equation, describing the flow stress as a function of deformation temperature and strain rate, has been developed, and the hot deformation activation energy was confirmed as 579.4 kJ/mol. Dynamic recrystallization (DRX) progress had been finished after increasing hot deformation temperature to 1100 °C at a strain rate of 100 s−1, leading to the obvious transformation from low-angle grain boundaries (LAGBs) to high-angle grain boundaries (HAGBs), and a relatively stable fraction of HAGBs was obtained. At a strain rate of 100 s−1, the β-fiber at {011} transited to {112} (C orientation), and finally a recrystallized orientation of {100} formed after absolute DRX. GDRX is the primary DRX mechanism, but DDRX mechanism is dominant with the increase in deformation temperature at a high strain rate of 100 s−1.

ACS Style

Qiuzhi Gao; Hailian Zhang; Huijun Li; Xin Zhang; Fu Qu; Yujiao Jiang; Ziyun Liu; Chenchen Jiang. Hot deformation of alumina-forming austenitic steel: EBSD study and flow behavior. Journal of Materials Science 2019, 54, 8760 -8777.

AMA Style

Qiuzhi Gao, Hailian Zhang, Huijun Li, Xin Zhang, Fu Qu, Yujiao Jiang, Ziyun Liu, Chenchen Jiang. Hot deformation of alumina-forming austenitic steel: EBSD study and flow behavior. Journal of Materials Science. 2019; 54 (11):8760-8777.

Chicago/Turabian Style

Qiuzhi Gao; Hailian Zhang; Huijun Li; Xin Zhang; Fu Qu; Yujiao Jiang; Ziyun Liu; Chenchen Jiang. 2019. "Hot deformation of alumina-forming austenitic steel: EBSD study and flow behavior." Journal of Materials Science 54, no. 11: 8760-8777.