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Haiyan Zhao
State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China

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Journal article
Published: 30 August 2021 in Additive Manufacturing
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Surface roughness is a serious concern in powder bed fusion (PBF) additive manufacturing, especially for aerospace and biomedical applications. An adequate surface quality of as-built products is desired due to difficulty in post-processing of interior sides and intricate geometries of printings. The side surface draws more attention than the top surface and a comprehensive understanding of side roughness mechanisms is required. However, observation of side roughness formation in experiments is yet difficult. In this paper, the formation process of the side surfaces in electron beam PBF is analyzed by a 3-D mesoscale multi-physics simulation, so as to provide an insight view into side roughness mechanisms from the scope of heat and mass transfer. The melting process and the resulting side surface morphologies of thin-walled parts are analyzed. It turns out that the melted traces in cases with a relatively low heat input generally have greater fluctuations than in cases with a high heat input, which leads to a higher side roughness. The investigation reveals that the melt pool flow driven by surface tension is the main cause of track shape fluctuation. This fluctuation is produced in essence by the random distribution of powder particles and the Plateau–Rayleigh instability, which describes the disintegration into a chain of drops. An analytical estimation of minimum limit of side roughness in as-built parts and the mechanisms for the generation of the side roughness are depicted systematically, based on which some improvement measures are proposed finally. This will help improve surface quality in metal additive manufacturing.

ACS Style

Chaochao Wu; Muhammad Qasim Zafar; Haiyan Zhao; You Wang; Christoph Schöler; Christian Heinigk; Markus Niessen; Wolfgang Schulz. Multi-physics modeling of side roughness generation mechanisms in powder bed fusion. Additive Manufacturing 2021, 102274 .

AMA Style

Chaochao Wu, Muhammad Qasim Zafar, Haiyan Zhao, You Wang, Christoph Schöler, Christian Heinigk, Markus Niessen, Wolfgang Schulz. Multi-physics modeling of side roughness generation mechanisms in powder bed fusion. Additive Manufacturing. 2021; ():102274.

Chicago/Turabian Style

Chaochao Wu; Muhammad Qasim Zafar; Haiyan Zhao; You Wang; Christoph Schöler; Christian Heinigk; Markus Niessen; Wolfgang Schulz. 2021. "Multi-physics modeling of side roughness generation mechanisms in powder bed fusion." Additive Manufacturing , no. : 102274.

Original article
Published: 09 August 2021 in The International Journal of Advanced Manufacturing Technology
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Molybdenum is a newly added material in additive manufacturing material cabinet, and it is under the spotlight owing to its crucial applications. The high-energy electron beam selective melting (EBSM) process is supposed to be a promising technique for molybdenum printing because of its vacuum environment. This paper presents EBSM numerical process simulation for molybdenum on macro- and mesoscale established with exclusive powder material modeling. Experimentally determined, process parameters are implemented in 3D macro- and 2D mesoscale models for a profound process insight. Primarily molybdenum powder material model is established, and a multi-track FEM simulation is performed to predict melt pool configuration, temperature field and phase transformation. Next, powder consolidation mechanism, side surface roughness, porosity, and voids are investigated through a CFD model, where the molybdenum particles are explicitly considered from the EBSM process viewpoint. Results proved the effectiveness of the numerical simulation for detailed EBSM process understanding for molybdenum material.

ACS Style

Muhammad Qasim Zafar; Chaochao Wu; Haiyan Zhao; Du Kai; Qianming Gong. Numerical simulation for electron beam selective melting PBF additive manufacturing of molybdenum. The International Journal of Advanced Manufacturing Technology 2021, 1 -14.

AMA Style

Muhammad Qasim Zafar, Chaochao Wu, Haiyan Zhao, Du Kai, Qianming Gong. Numerical simulation for electron beam selective melting PBF additive manufacturing of molybdenum. The International Journal of Advanced Manufacturing Technology. 2021; ():1-14.

Chicago/Turabian Style

Muhammad Qasim Zafar; Chaochao Wu; Haiyan Zhao; Du Kai; Qianming Gong. 2021. "Numerical simulation for electron beam selective melting PBF additive manufacturing of molybdenum." The International Journal of Advanced Manufacturing Technology , no. : 1-14.

Original article
Published: 18 February 2021 in The International Journal of Advanced Manufacturing Technology
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Powder bed fusion (PBF) process is expeditely moving towards its maturity for the direct manufacturing of intricated and sophisticated metallic parts. The typical process is instead complex and yet challenging to interpret experimentally. Modeling and simulation strategy has been widely implemented to comprehend and optimize the process. Therefore, an integrated simulation approach incorporating stochastic powder deposition and subsequently selective melting is developed to understand the consolidation mechanism in a multilayer process of electron beam PBF additive manufacturing. Simulation results of a thin-walled cross section are validated with the published experimental data to demonstrate the effectiveness of the proposed model. The simulation results of the multilayer process revealed that the layer thickness keeps on slight changes until reaching a steady state during the multilayer additive process. The stable powder layer thickness is systematically analyzed, which proved that the influence of the wall effect should be considered in smaller nominal layer thickness and denser powder bed. Finally, the printing quality in the multilayer process is dependent on adequate inter- and intra-layer bonding when the layer thickness reaches its maximum value, where agglomeration and balling effect in melt pool dynamics predominant by surface tension play crucial roles.

ACS Style

Chaochao Wu; Muhammad Qasim Zafar; Haiyan Zhao. Numerical investigation of consolidation mechanism in powder bed fusion considering layer characteristics during multilayer process. The International Journal of Advanced Manufacturing Technology 2021, 113, 2087 -2100.

AMA Style

Chaochao Wu, Muhammad Qasim Zafar, Haiyan Zhao. Numerical investigation of consolidation mechanism in powder bed fusion considering layer characteristics during multilayer process. The International Journal of Advanced Manufacturing Technology. 2021; 113 (7-8):2087-2100.

Chicago/Turabian Style

Chaochao Wu; Muhammad Qasim Zafar; Haiyan Zhao. 2021. "Numerical investigation of consolidation mechanism in powder bed fusion considering layer characteristics during multilayer process." The International Journal of Advanced Manufacturing Technology 113, no. 7-8: 2087-2100.

Research paper
Published: 09 August 2020 in Welding in the World
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Microstructure and mechanical properties of 6061-T6 aluminum alloy/304 stainless steel (Al/steel) joints welded by inertia friction (IFW) and continuous drive friction (CDFW) were studied comparatively. Morphology, microstructure, interfacial composition, and mechanical properties of Al/steel joints were investigated. Results showed that an intermetallic compound (IMC) reaction layer was formed at the welding interface in the CDFWed joint, and wider and clearer than that of the IFWed joint. The high concentration Si was observed at the welding interface. The grain of fully dynamic recrystallized zone (FDRZ) was below 0.1 μm in both joints, and the average width of FDRZ in the IFWed joint and CDFWed joint was about 5 μm and 2 μm, respectively. FDRZ had the high hardness, and the hardness value of IFWed joint was higher than that of CDFWed joint. The maximum tensile strength of IFWed joint was higher than that of CDFWed joint, and the reason should be related to the thickness of IMC at the welding interface.

ACS Style

Yong Liu; Haiyan Zhao; Yun Peng; Xiaofei Ma. Microstructure and tensile strength of aluminum/stainless steel joint welded by inertia friction and continuous drive friction. Welding in the World 2020, 64, 1799 -1809.

AMA Style

Yong Liu, Haiyan Zhao, Yun Peng, Xiaofei Ma. Microstructure and tensile strength of aluminum/stainless steel joint welded by inertia friction and continuous drive friction. Welding in the World. 2020; 64 (10):1799-1809.

Chicago/Turabian Style

Yong Liu; Haiyan Zhao; Yun Peng; Xiaofei Ma. 2020. "Microstructure and tensile strength of aluminum/stainless steel joint welded by inertia friction and continuous drive friction." Welding in the World 64, no. 10: 1799-1809.

Original article
Published: 25 July 2020 in The International Journal of Advanced Manufacturing Technology
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Electron beam melting (EBM®) is a metallic printing process that has become increasingly sophisticated over the past decade. The formation of residual stress due to a high-energy electron beam is considered a primary hindrance in the maturation of the process itself and, subsequently, the quality of the printed parts. Contrary to hit and trial, the finite element method (FEM) has become a prevalent technique for estimating residual stresses and subsequent distortion in additive manufacturing chunks. Since the EBM® is a powder bed fusion (PBF) process, powder material properties are substantially different from those of solid and undoubtedly important for efficient simulation. Several reviews have been published on FEM applications in additive manufacturing so far; however, a straightforward solution for material modeling from EBM® viewpoint is still needed. This critical review paper is an attempt to propose a material modeling approach to establish an adequate FEM model for EBM® process simulation.

ACS Style

Muhammad Qasim Zafar; Chao Chao Wu; Haiyan Zhao; Jinnan Wang; Xingjian Hu. Finite element framework for electron beam melting process simulation. The International Journal of Advanced Manufacturing Technology 2020, 109, 2095 -2112.

AMA Style

Muhammad Qasim Zafar, Chao Chao Wu, Haiyan Zhao, Jinnan Wang, Xingjian Hu. Finite element framework for electron beam melting process simulation. The International Journal of Advanced Manufacturing Technology. 2020; 109 (7-8):2095-2112.

Chicago/Turabian Style

Muhammad Qasim Zafar; Chao Chao Wu; Haiyan Zhao; Jinnan Wang; Xingjian Hu. 2020. "Finite element framework for electron beam melting process simulation." The International Journal of Advanced Manufacturing Technology 109, no. 7-8: 2095-2112.

Technical paper
Published: 26 November 2019 in Microsystem Technologies
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Polyimide microfluidic devices (MFDs) have been attached enormous significance because of its excellent organic-solvent inertness, biocompatibility, and thermal stability. In this paper, a novel fabrication method based on the thought of additive manufacturing, which is adding materials layer by layer from bottom to top, was used to construct a multilayer polyimide MFD. The MFD has sophisticated three-dimensional (3D) microchannels with adjustable cross-sectional geometries and high bonding strength, which leads to good reagent mixing performance, large surface-to-volume ratio, and great durability. Starting from a single polyimide film, ultraviolet (UV) laser was utilized to ablate microchannels on the film. Due to the studies over the influence of UV laser on the channel width, the microchannel edge shape is under control, varying from trapezoid to rectangle. From monolayer to multilayer MFDs, thermal bonding with fluorinated ethylene propylene (FEP) nanoparticle dispersion as the adhesive was adopted to stack polyimide films tightly with precise alignment. In this way, microchannels can be connected vertically between layers to form 3D structures. Besides, a homogeneous adhesive interlayer and polyimide-FEP mixing regime were formed, which can provide high bonding strength. Results of computational fluid dynamics simulation of 3D microchannel structures and organic synthesis experiment revealed that our device has great reagent mixing efficiency and promising application prospects in diverse research fields, especially organic chemical and biological studies.

ACS Style

Xingjian Hu; Fan Yang; Mingzhao Guo; Jiayun Pei; Haiyan Zhao; Yujun Wang. Fabrication of polyimide microfluidic devices by laser ablation based additive manufacturing. Microsystem Technologies 2019, 26, 1573 -1583.

AMA Style

Xingjian Hu, Fan Yang, Mingzhao Guo, Jiayun Pei, Haiyan Zhao, Yujun Wang. Fabrication of polyimide microfluidic devices by laser ablation based additive manufacturing. Microsystem Technologies. 2019; 26 (5):1573-1583.

Chicago/Turabian Style

Xingjian Hu; Fan Yang; Mingzhao Guo; Jiayun Pei; Haiyan Zhao; Yujun Wang. 2019. "Fabrication of polyimide microfluidic devices by laser ablation based additive manufacturing." Microsystem Technologies 26, no. 5: 1573-1583.

Journal article
Published: 03 September 2019 in Ceramics International
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In this study, the multifunctional carbon nitride based composite graphitic-C3N4 (g-C3N4)/TiO2/Ag was prepared through a simple and efficient vacuum freeze-drying route. TiO2 and Ag nanoparticles were demonstrated to decorate onto the surface of g-C3N4 sheet. In the ultraviolet–visible absorption test, a narrower band gap and red-shift of light absorption edge were observed for g-C3N4/TiO2/Ag compared to pristine g-C3N4 and single-component modified g-C3N4/TiO2. The photodegradation property of g-C3N4/TiO2/Ag was investigated toward the degradation of methylene blue (abbreviated as MB) under the irradiation of visible light. These results indicated that the degradation performance of organic dyes for g-C3N4/TiO2/Ag was obviously improved compared with g-C3N4/TiO2 and g-C3N4. The reaction rate constant of MB degradation for g-C3N4/TiO2/Ag was 4.24 times higher than that of pristine g-C3N4. In addition, such rationally constructed nanocomposite presented evidently enhanced antibacterial performance against the Gram-negative Escherichia coli. Concentration dependent antibacterial performance was systematically investigated. And 84% bacterial cell viability loss had been observed at 500 μg/mL g-C3N4/TiO2/Ag within 2 h visible light irradiation.

ACS Style

Dong Yan; Xin Wu; Jiayun Pei; Chaochao Wu; Xiumei Wang; Haiyan Zhao. Construction of g-C3N4/TiO2/Ag composites with enhanced visible-light photocatalytic activity and antibacterial properties. Ceramics International 2019, 46, 696 -702.

AMA Style

Dong Yan, Xin Wu, Jiayun Pei, Chaochao Wu, Xiumei Wang, Haiyan Zhao. Construction of g-C3N4/TiO2/Ag composites with enhanced visible-light photocatalytic activity and antibacterial properties. Ceramics International. 2019; 46 (1):696-702.

Chicago/Turabian Style

Dong Yan; Xin Wu; Jiayun Pei; Chaochao Wu; Xiumei Wang; Haiyan Zhao. 2019. "Construction of g-C3N4/TiO2/Ag composites with enhanced visible-light photocatalytic activity and antibacterial properties." Ceramics International 46, no. 1: 696-702.

Original article
Published: 22 August 2019 in The International Journal of Advanced Manufacturing Technology
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Aluminum alloy and stainless steel were joined by a continuous-drive axial friction welding machine in this study. The effects of welding parameters on the morphology, microstructure, microhardness, tensile strength, and fracture surface of dissimilar joints were analyzed. The distribution, thickness, and composition of intermetallic compound (IMC) were also discussed. Results showed that the formation of flash only was on the aluminum side because 6061 Al underwent extensive deformation during welding. Al and Fe elements diffused at the bonding interface and formed the IMC layer. The IMC thickness near the 1/2 radius was the smallest, and the thinnest at the center region. With the increase of friction pressure, the tensile strength of joint first increased and then decreased. When forge pressure was below 220 MPa, joint strength was approximately linearly related to the forge pressure. Edge regions of joints had achieved metallurgical bonding. The central region was the weak joining, and the fracture surface contained some cracks, IMCs, and a small amount of dimples.

ACS Style

Yong Liu; Haiyan Zhao; Yun Peng; Xiaofei Ma. Microstructure characterization and mechanical properties of the continuous-drive axial friction welded aluminum/stainless steel joint. The International Journal of Advanced Manufacturing Technology 2019, 104, 4399 -4408.

AMA Style

Yong Liu, Haiyan Zhao, Yun Peng, Xiaofei Ma. Microstructure characterization and mechanical properties of the continuous-drive axial friction welded aluminum/stainless steel joint. The International Journal of Advanced Manufacturing Technology. 2019; 104 (9-12):4399-4408.

Chicago/Turabian Style

Yong Liu; Haiyan Zhao; Yun Peng; Xiaofei Ma. 2019. "Microstructure characterization and mechanical properties of the continuous-drive axial friction welded aluminum/stainless steel joint." The International Journal of Advanced Manufacturing Technology 104, no. 9-12: 4399-4408.

Research paper
Published: 17 August 2019 in Welding in the World
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Mechanical properties of aluminum alloy/stainless steel joint including tensile strength, bending angle, impact toughness, and fatigue property were evaluated, and the effects of friction pressure and rotational speed were also discussed in this work. Results showed that the intermetallic compound (IMC) layer was formed at the bonding interface of the joint, and a thicker IMC layer was observed in the outer region of the joint, and the thickness decreased slightly in the edge region. The thickness of the IMC layer increased with increasing rotational speed. As friction pressure increased, the tensile strength of the joint gradually increased. Joint strength reached to the maximum tensile strength of 323 MPa when the rotational speed and friction pressure were 1100 rpm and 180 MPa, respectively. With the increase of friction pressure, the bending angle of the joint first increased and then decreased. The bending angle reached to 94°, and the welded joint had the excellent bending ductility. The average impact-absorbing energy of joints was 14.47 J, and the maximum fatigue cycle number of joints could reach to 1.25 × 105.

ACS Style

Yong Liu; Haiyan Zhao; Yun Peng; Xiaofei Ma. Mechanical properties of the inertia friction welded aluminum/stainless steel joint. Welding in the World 2019, 63, 1601 -1611.

AMA Style

Yong Liu, Haiyan Zhao, Yun Peng, Xiaofei Ma. Mechanical properties of the inertia friction welded aluminum/stainless steel joint. Welding in the World. 2019; 63 (6):1601-1611.

Chicago/Turabian Style

Yong Liu; Haiyan Zhao; Yun Peng; Xiaofei Ma. 2019. "Mechanical properties of the inertia friction welded aluminum/stainless steel joint." Welding in the World 63, no. 6: 1601-1611.

Journal article
Published: 21 July 2019 in Metals
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Plates (37 mm thick) of 6005A-T6 aluminum alloy were butt joined by a single-sided and double-sided friction stir welding (FSW). The 3D residual stresses in the joints were determined using neutron diffraction. The microstructures were characterized by a transmission electron microscope (TEM) and electron backscatter diffraction (EBSD). In the single-sided FSW specimen, there were acceptable mechanical properties with a tensile strength of 74.4% of base metal (BM) and low residual stresses with peak magnitudes of approximately 37.5% yield strength of BM were achieved. The hardness is related to the grain size of the nugget zone (NZ), and in this study, precipitations were dissolved due to the high heat input. In the double-sided FSW specimen, there were good mechanical properties with a tensile strength of 80.8% of BM, but high residual stresses with peak magnitudes of approximately 70% yield strength of BM were obtained. The heat input by the second pass provided an aging environment for the first-pass weld zone where the dissolved phases were precipitated and residual stresses were relaxed.

ACS Style

Xiaolong Liu; Pu Xie; Robert Wimpory; Wenya Li; Ruilin Lai; Meijuan Li; Dongfeng Chen; Yuntao Liu; Haiyan Zhao. Residual Stress, Microstructure and Mechanical Properties in Thick 6005A-T6 Aluminium Alloy Friction Stir Welds. Metals 2019, 9, 803 .

AMA Style

Xiaolong Liu, Pu Xie, Robert Wimpory, Wenya Li, Ruilin Lai, Meijuan Li, Dongfeng Chen, Yuntao Liu, Haiyan Zhao. Residual Stress, Microstructure and Mechanical Properties in Thick 6005A-T6 Aluminium Alloy Friction Stir Welds. Metals. 2019; 9 (7):803.

Chicago/Turabian Style

Xiaolong Liu; Pu Xie; Robert Wimpory; Wenya Li; Ruilin Lai; Meijuan Li; Dongfeng Chen; Yuntao Liu; Haiyan Zhao. 2019. "Residual Stress, Microstructure and Mechanical Properties in Thick 6005A-T6 Aluminium Alloy Friction Stir Welds." Metals 9, no. 7: 803.

Journal article
Published: 01 December 2018 in Materials Science Forum
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In this work, both Finite element simulated method and contour method experimental measurement are used to obtain residual stresses of different Titanium welded alloys, the results show that the maximum of the residual stress is mainly related to the internal restraint degree which formed inside of the thickness, the distribution of the residual stress depends primarily on the shape of weld shape. The heating stage plays a major role in relaxing the residual stress in this research. 95% of the residual stress is relieved in the temperature rising period, and about 75% of it is relieved in the temperature rising period when the temperature is above 500°C.

ACS Style

Hai Yan Zhao; Pu Xie. Evaluation on Residual Stresses in Thick Titanium Welded Alloys. Materials Science Forum 2018, 941, 1095 -1098.

AMA Style

Hai Yan Zhao, Pu Xie. Evaluation on Residual Stresses in Thick Titanium Welded Alloys. Materials Science Forum. 2018; 941 ():1095-1098.

Chicago/Turabian Style

Hai Yan Zhao; Pu Xie. 2018. "Evaluation on Residual Stresses in Thick Titanium Welded Alloys." Materials Science Forum 941, no. : 1095-1098.

Review
Published: 16 August 2018 in Molecules
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DNA detection with high sensitivity and specificity has tremendous potential as molecular diagnostic agents. Graphene and graphene-based nanomaterials, such as graphene nanopore, graphene nanoribbon, graphene oxide, and reduced graphene oxide, graphene-nanoparticle composites, were demonstrated to have unique properties, which have attracted increasing interest towards the application of DNA detection with improved performance. This article comprehensively reviews the most recent trends in DNA detection based on graphene and graphene-related nanomaterials. Based on the current understanding, this review attempts to identify the future directions in which the field is likely to thrive, and stimulate more significant research in this subject.

ACS Style

Xin Wu; Fengwen Mu; Yinghui Wang; Haiyan Zhao. Graphene and Graphene-Based Nanomaterials for DNA Detection: A Review. Molecules 2018, 23, 2050 .

AMA Style

Xin Wu, Fengwen Mu, Yinghui Wang, Haiyan Zhao. Graphene and Graphene-Based Nanomaterials for DNA Detection: A Review. Molecules. 2018; 23 (8):2050.

Chicago/Turabian Style

Xin Wu; Fengwen Mu; Yinghui Wang; Haiyan Zhao. 2018. "Graphene and Graphene-Based Nanomaterials for DNA Detection: A Review." Molecules 23, no. 8: 2050.

Journal article
Published: 05 December 2016 in Materials Science and Engineering: C
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Novel two-dimensional materials with a layered structure are of special interest for a variety of promising applications. In current research, the nanostructured graphene oxide-Fe2O3 composite (GO-Fe2O3) was firstly obtained via a carefully elaborated approach of vacuum freeze-drying. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images revealed that α-Fe2O3 nanoparticles loaded well on the surfaces of graphene. A series of characterization were performed to further elucidate the as-obtained nanomaterial's physicochemical properties. These results suggested the current route could be further extended to obtain the other kinds of two-dimensional materials based composites. For the sake of extending the potential application of herein achieved graphene composites, its cytotoxicity assessment on HeLa cells was systematically investigated. CCK-8 assay in HeLa cells treated by GO-Fe2O3 showed dose- (1–100 μg/ml) and time- (24–48 h) dependent cytotoxicity, which was comparable to that of GO. The excess generation of intracellular reactive oxygen species (ROS) induced by these nanomaterials was responsible for the cytotoxicity. TEM analysis vividly illustrated GO-Fe2O3 internalized by HeLa cells in endomembrane compartments such as lysosomes, and degraded through autophagic pathway. The detrimental biological consequence accompanied by cell internalization was limited. Based on the above results, it expected to render useful information for the development of new and popular strategies to design graphene-based composites, as well as deep insights into the mechanism of graphene-based composites cytotoxicity for further potential application.

ACS Style

Dong Yan; Haiyan Zhao; Jiayun Pei; Xin Wu; Yue Liu. The rational designed graphene oxide-Fe 2 O 3 composites with low cytotoxicity. Materials Science and Engineering: C 2016, 72, 659 -666.

AMA Style

Dong Yan, Haiyan Zhao, Jiayun Pei, Xin Wu, Yue Liu. The rational designed graphene oxide-Fe 2 O 3 composites with low cytotoxicity. Materials Science and Engineering: C. 2016; 72 ():659-666.

Chicago/Turabian Style

Dong Yan; Haiyan Zhao; Jiayun Pei; Xin Wu; Yue Liu. 2016. "The rational designed graphene oxide-Fe 2 O 3 composites with low cytotoxicity." Materials Science and Engineering: C 72, no. : 659-666.

Article
Published: 19 May 2015 in Experimental Mechanics
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The residual stresses in electron beam welded Titanium alloy before and after post weld heat treatment (PWHT) are measured by both of the contour method and X-ray diffraction method. The application of X-ray diffraction method on the surface of welded structure was used to confirm the results of the contour method induced by interpolation from CMM measuring position which is limited near the structure surface. The welding residual stresses are characterized, as well as the residual stress relaxation by PWHT at soaking temperatures of 500 and 650 °C and holding times ranging from 0 min to 2 h respectively. The measured results show that the maximum welding residual stress without PWHT is 550 MPa located inside the plate. The relaxation of the residual stresses from PWHT mainly depend on soaking temperature, and occurs most both in the heating stage and holding stage. The residual stresses are reduced to a limited value after the PWHT with soaking temperature of 650 °C and 2 h.

ACS Style

Pingxing Xie; Hui Zhao; Bin Wu; Shouliang Gong. Evaluation of Residual Stresses Relaxation by Post Weld Heat Treatment Using Contour Method and X-ray Diffraction Method. Experimental Mechanics 2015, 55, 1329 -1337.

AMA Style

Pingxing Xie, Hui Zhao, Bin Wu, Shouliang Gong. Evaluation of Residual Stresses Relaxation by Post Weld Heat Treatment Using Contour Method and X-ray Diffraction Method. Experimental Mechanics. 2015; 55 (7):1329-1337.

Chicago/Turabian Style

Pingxing Xie; Hui Zhao; Bin Wu; Shouliang Gong. 2015. "Evaluation of Residual Stresses Relaxation by Post Weld Heat Treatment Using Contour Method and X-ray Diffraction Method." Experimental Mechanics 55, no. 7: 1329-1337.

Article
Published: 01 May 2015 in Acta Metallurgica Sinica (English Letters)
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This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates (50 mm thick) by using finite element and contour measurement methods. A three-dimensional finite element model of 50-mm-thick titanium component was proposed, in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software. Considering the uncertainty of welding simulation, the computation was calibrated by experimental data of contour measurement method. Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint. The peak tensile stress exceeds the yield strength of base materials inside weld, which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.

ACS Style

Pu Xie; Hai-Yan Zhao; Bing Wu; Shui-Li Gong. Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding. Acta Metallurgica Sinica (English Letters) 2015, 28, 922 -930.

AMA Style

Pu Xie, Hai-Yan Zhao, Bing Wu, Shui-Li Gong. Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding. Acta Metallurgica Sinica (English Letters). 2015; 28 (7):922-930.

Chicago/Turabian Style

Pu Xie; Hai-Yan Zhao; Bing Wu; Shui-Li Gong. 2015. "Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding." Acta Metallurgica Sinica (English Letters) 28, no. 7: 922-930.

Journal article
Published: 20 March 2008 in Frontiers of Materials Science in China
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The electron beam could be controlled by magnetic field for fast deflection, in which way multi-beam could be produced by deflection technique. The multi-beams run simultaneously for material processing with different heat input and positions. Therefore, it is possible to adjust the thermal effects and optimize the process. In this paper, the generation of multi-beams in electron beam welding (EBW) was investigated, and the processes of EBW with multi-beams were also investigated by both the numerical simulation methods, i.e., finite element analysis (FEA), and the experiments. The result shows that the residual stress of EBW could be minimized by using the multiple beam technique, and at the same time the welding deformation could also be reduced with the optimized parameters.

ACS Style

Hai-Yan Zhao; Xin Wang; Xi-Chang Wang; Yong-Ping Lei. Reduction of residual stress and deformation in electron beam welding by using multiple beam technique. Frontiers of Materials Science in China 2008, 2, 66 -71.

AMA Style

Hai-Yan Zhao, Xin Wang, Xi-Chang Wang, Yong-Ping Lei. Reduction of residual stress and deformation in electron beam welding by using multiple beam technique. Frontiers of Materials Science in China. 2008; 2 (1):66-71.

Chicago/Turabian Style

Hai-Yan Zhao; Xin Wang; Xi-Chang Wang; Yong-Ping Lei. 2008. "Reduction of residual stress and deformation in electron beam welding by using multiple beam technique." Frontiers of Materials Science in China 2, no. 1: 66-71.