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Cold spray additive manufacturing (CSAM) is a solid-state deposition process well-suited to titanium that has the potential to make large, near-net-shape parts at high productivity. However, further research is required to truly accomplish the freedom of design expected from CSAM and, in particular, to address how to manufacture a specific 3D object with minimal porosity. Therefore, this paper focuses on understanding how tool path planning strategy and robot kinematics affect the geometry and porosity distribution in a 3D object. Square titanium frames were manufactured layer-by-layer using a continuous tool path planning strategy in which the contour spray angle, traverse speed and corner smoothing radius were varied selectively. The sample geometry was analysed by 3D laser scanning, and the capacity to produce straight, vertical walls and square corners were demonstrated. The total porosity in the manufactured objects was measured using the Archimedes’ principle, further investigated by metallographic cross-section analysis, and then validated by X-ray computed tomography on selected samples. Porosity was distributed layer by layer, creating a fishbone structure in the cross-section with higher porosity between the layers and near the edges of the walls and corners. The influence of robot kinematics and toolpath planning on forming underbuilt and overbuilt structures and how they influenced porosity development are also discussed. The knowledge generated from this research can significantly influence the development of tool path planning strategies in CSAM, providing the means to produce improved near-net-shapes with controlled porosity formation.
Alejandro Vargas-Uscategui; Peter C. King; Sam Yang; Clement Chu; Jianli Li. Toolpath planning for cold spray additively manufactured titanium walls and corners: Effect on geometry and porosity. Journal of Materials Processing Technology 2021, 298, 117272 .
AMA StyleAlejandro Vargas-Uscategui, Peter C. King, Sam Yang, Clement Chu, Jianli Li. Toolpath planning for cold spray additively manufactured titanium walls and corners: Effect on geometry and porosity. Journal of Materials Processing Technology. 2021; 298 ():117272.
Chicago/Turabian StyleAlejandro Vargas-Uscategui; Peter C. King; Sam Yang; Clement Chu; Jianli Li. 2021. "Toolpath planning for cold spray additively manufactured titanium walls and corners: Effect on geometry and porosity." Journal of Materials Processing Technology 298, no. : 117272.
Cold spray is emerging as an additive manufacturing technique, particularly advantageous when high production rate and large build sizes are in demand. To further accelerate technology’s industrial maturity, the problem of geometric control must be improved, and a neural network model has emerged to predict additively manufactured geometry. However, limited data on the effect of deposition conditions on geometry growth is often problematic. Therefore, this study presents data-efficient neural network modelling of a single-track profile in cold spray additive manufacturing. Two modelling techniques harnessing prior knowledge or existing model were proposed, and both were found to be effective in achieving the data-efficient development of a neural network model. We also showed that the proposed data-efficient neural network model provided better predictive performance than the previously proposed Gaussian function model and purely data-driven neural network. The results indicate that a neural network model can outperform a widely used mathematical model with data-efficient modelling techniques and be better suited to improving geometric control in cold spray additive manufacturing.
Daiki Ikeuchi; Alejandro Vargas-Uscategui; Xiaofeng Wu; Peter King. Data-Efficient Neural Network for Track Profile Modelling in Cold Spray Additive Manufacturing. Applied Sciences 2021, 11, 1654 .
AMA StyleDaiki Ikeuchi, Alejandro Vargas-Uscategui, Xiaofeng Wu, Peter King. Data-Efficient Neural Network for Track Profile Modelling in Cold Spray Additive Manufacturing. Applied Sciences. 2021; 11 (4):1654.
Chicago/Turabian StyleDaiki Ikeuchi; Alejandro Vargas-Uscategui; Xiaofeng Wu; Peter King. 2021. "Data-Efficient Neural Network for Track Profile Modelling in Cold Spray Additive Manufacturing." Applied Sciences 11, no. 4: 1654.
In cold spray additive manufacturing (CSAM), the severe plastic deformation of the input powder particles leads to an accumulation of residual stresses, the magnitude of which is affected by process conditions. In the current study, the effects of traverse speed and powder feed rate on the residual stress state were investigated in commercially pure titanium cylinders produced by CSAM. Residual stress measurements were made in a grid pattern covering the 2D cross section using the KOWARI neutron diffractometer at ANSTO, Australia, and selected results were validated using the contour method. It was found that the thermal effect was dominant on the residual stress state generating a tensile state near the inner and outer surfaces of the cylinder walls while compressive residual stresses tend to accumulate in the center of the wall. The residual stresses were dominated by thermal stresses at low traverse speed, while peening becomes more critical at high traverse speeds. Increasing the powder feed rate increased the magnitude of the residual stresses. High traverse speeds and low feed rates are beneficial for producing 3D parts by CSAM. However, slow traverse speeds are more detrimental than high feed rates for a given layer thickness.
Alejandro Vargas-Uscategui; Peter King; Mark J. Styles; Michael Saleh; Vladimir Luzin; Kevin Thorogood. Residual Stresses in Cold Spray Additively Manufactured Hollow Titanium Cylinders. Journal of Thermal Spray Technology 2020, 29, 1508 -1524.
AMA StyleAlejandro Vargas-Uscategui, Peter King, Mark J. Styles, Michael Saleh, Vladimir Luzin, Kevin Thorogood. Residual Stresses in Cold Spray Additively Manufactured Hollow Titanium Cylinders. Journal of Thermal Spray Technology. 2020; 29 (6):1508-1524.
Chicago/Turabian StyleAlejandro Vargas-Uscategui; Peter King; Mark J. Styles; Michael Saleh; Vladimir Luzin; Kevin Thorogood. 2020. "Residual Stresses in Cold Spray Additively Manufactured Hollow Titanium Cylinders." Journal of Thermal Spray Technology 29, no. 6: 1508-1524.
A non-equiatomic Fe50Mn30Co10Cr10 alloy was prepared by laser cladding, and the effects of boron addition on the microstructure, hardness and abrasive wear-resistance were investigated. Elemental powders were mixed using an attritor mill for 30 h and then applied by laser cladding on a stainless steel 316L substrate. The effect of boron addition (0.1, 0.66 and 5.40 at%) on the alloy microstructure was assessed using optical and electron microscopy, and the phase composition was studied using X-ray diffraction. The laser claddings were exposed to abrasive wear conditions using the dry sand/rubber wheel test. The microstructure of the laser claddings exhibited columnar dendrites formed by two crystalline structures (fcc and hcp) with the same chemical composition. The hcp structure was the result of the partial martensitic transformation of the fcc structure. Boron addition led to the formation of a eutectic phase along the interdendritic regions with a crystalline structure consistent with M2B-type borides (M = Cr, Fe). Hardness and abrasive wear-resistance of the laser claddings were strongly influenced by boron content. When boron content was increased from 0 at% to 5.40 at% the microhardness of the material was from 291 HV to 445 HV. Similarly, the boron content improved the behaviour against abrasive wear due to the increased volume fraction of borides in the microstructure. The high content of the boride phase in the laser cladding with 5.40 at% B allowed reducing the abrasive wear rate by more than 30% when compared with the alloy without boron content.
Jose Y. Aguilar-Hurtado; Alejandro Vargas-Uscategui; Katherine Paredes-Gil; Rodrigo Palma-Hillerns; Maria J. Tobar; Jose M. Amado. Boron addition in a non-equiatomic Fe50Mn30Co10Cr10 alloy manufactured by laser cladding: Microstructure and wear abrasive resistance. Applied Surface Science 2020, 515, 146084 .
AMA StyleJose Y. Aguilar-Hurtado, Alejandro Vargas-Uscategui, Katherine Paredes-Gil, Rodrigo Palma-Hillerns, Maria J. Tobar, Jose M. Amado. Boron addition in a non-equiatomic Fe50Mn30Co10Cr10 alloy manufactured by laser cladding: Microstructure and wear abrasive resistance. Applied Surface Science. 2020; 515 ():146084.
Chicago/Turabian StyleJose Y. Aguilar-Hurtado; Alejandro Vargas-Uscategui; Katherine Paredes-Gil; Rodrigo Palma-Hillerns; Maria J. Tobar; Jose M. Amado. 2020. "Boron addition in a non-equiatomic Fe50Mn30Co10Cr10 alloy manufactured by laser cladding: Microstructure and wear abrasive resistance." Applied Surface Science 515, no. : 146084.
Cold spray additive manufacturing is an emerging technology that offers the ability to deposit oxygen-sensitive materials and to manufacture large components in the solid state. For further development of the technology, the geometric control of cold sprayed components is fundamental but not yet fully matured. This study presents a neural network predictive modelling of a single-track profile in cold spray additive manufacturing to address the problem. In contrast to previous studies focusing only on key geometric feature predictions, the neural network model was employed to demonstrate its capability of predicting complete track profiles at both normal and off-normal spray angles, resulting in a mean absolute error of 8.3%. We also compared the track profile modelling results against the previously proposed Gaussian model and showed that the neural network model provided comparable predictive accuracy, even outperforming in the predictions at cold spray profile edges. The results indicate that a neural network modelling approach is well suited to cold spray profile prediction and may be used to improve geometric control during additive manufacturing with an appropriate process planning algorithm.
Daiki Ikeuchi; Alejandro Vargas-Uscategui; Xiaofeng Wu; Peter C. King. Neural Network Modelling of Track Profile in Cold Spray Additive Manufacturing. Materials 2019, 12, 2827 .
AMA StyleDaiki Ikeuchi, Alejandro Vargas-Uscategui, Xiaofeng Wu, Peter C. King. Neural Network Modelling of Track Profile in Cold Spray Additive Manufacturing. Materials. 2019; 12 (17):2827.
Chicago/Turabian StyleDaiki Ikeuchi; Alejandro Vargas-Uscategui; Xiaofeng Wu; Peter C. King. 2019. "Neural Network Modelling of Track Profile in Cold Spray Additive Manufacturing." Materials 12, no. 17: 2827.
High and Medium- Entropy Alloys (HEAs and MEAs) are a novel type of materials, which due to the reduction in configurational entropy, can offer an excellent combination of properties, such as, high strength, high ductility and moderate hardness. During the study, four alloys based on Fe50-XMn30Co10Cr10BX system (x = 0, 0.3, 0.6 and 1.7 wt. %) were manufactured by arc melting. The microstructure of the materials was analysed by optical microscopy, scanning electron microscopy, and X-ray diffraction. The Vickers microhardness of these alloys were also measured. Detailed characterization revealed the formation of a dual-phase matrix (fcc + hcp) due to the reduction in the stability of the fcc phase that led to a thermal induced partial martensitic transformation into a ε-hcp phase. The addition of boron promoted the formation of M2B-type borides (M = Cr, Fe), whose content increased with the addition of B. Changes in the phase composition, specifically the decrease of the hcp phase, were mainly due to the loss of manganese content. The microstrain analysis showed the absence of residual stresses in the crystal lattice due to a decrease in the dislocation’s density after the martensitic transformation. When boron content was brought from 0 wt.% to 1.7 wt.%, the microhardness of the material increased from 296HV to 452 HV, which is comparable to the microhardness of high-manganese steel. Finally, the thermodynamic parameter Φ was calculated using a phase prediction package AlloyASAP, allowing to establish that boron addition to Fe50Mn30Co10Cr10 originated medium-entropy alloys (Φ1).
Jose Y. Aguilar-Hurtado; Alejandro Vargas-Uscategui; Dario Zambrano-Mera; Rodrigo Palma-Hillerns. The effect of boron content on the microstructure and mechanical properties of Fe50-XMn30Co10Cr10BX (x = 0, 0.3, 0.6 and 1.7 wt%) multi-component alloys prepared by arc-melting. Materials Science and Engineering: A 2019, 748, 244 -252.
AMA StyleJose Y. Aguilar-Hurtado, Alejandro Vargas-Uscategui, Dario Zambrano-Mera, Rodrigo Palma-Hillerns. The effect of boron content on the microstructure and mechanical properties of Fe50-XMn30Co10Cr10BX (x = 0, 0.3, 0.6 and 1.7 wt%) multi-component alloys prepared by arc-melting. Materials Science and Engineering: A. 2019; 748 ():244-252.
Chicago/Turabian StyleJose Y. Aguilar-Hurtado; Alejandro Vargas-Uscategui; Dario Zambrano-Mera; Rodrigo Palma-Hillerns. 2019. "The effect of boron content on the microstructure and mechanical properties of Fe50-XMn30Co10Cr10BX (x = 0, 0.3, 0.6 and 1.7 wt%) multi-component alloys prepared by arc-melting." Materials Science and Engineering: A 748, no. : 244-252.
A flowmodel is formulated to investigate the hydrodynamic structure of the boundary layers of incompressible fluid in a rotating cylindrical cavity with steady radial inflow. The model considers mass and momentum transfer coupled between boundary layers and an inviscid core region. Dimensionless equations of motion are solved using integral methods and a space-marching technique. As the fluid moves radially inward, entraining boundary layers develop which can either meet or become non-entraining. Pressure and wall shear stress distributions, as well as velocity profiles predicted by the model, are compared to numerical simulations using the software OpenFOAM. Hydrodynamic structure of the boundary layers is governed by a Reynolds number,Re, a Rossby number, Ro, and the dimensionless radial velocity component at the periphery of the cavity, Uo. Results show that boundary layers merge for Re < < 10 and Ro > > 0.1, and boundary layers become predominantly non-entraining for low Ro, low Re, and high Uo. Results may contribute to improve the design of technology, such as heat exchange devices, and turbomachinery.
Benjamin Herrmann; Williams Calderón-Muñoz; Eduardo A. Salas; Alejandro Vargas Uscategui; Manuel Duarte-Mermoud; Diego A. Torres. Hydrodynamic structure of the boundary layers in a rotating cylindrical cavity with radial inflow. Physics of Fluids 2016, 28, 033601 .
AMA StyleBenjamin Herrmann, Williams Calderón-Muñoz, Eduardo A. Salas, Alejandro Vargas Uscategui, Manuel Duarte-Mermoud, Diego A. Torres. Hydrodynamic structure of the boundary layers in a rotating cylindrical cavity with radial inflow. Physics of Fluids. 2016; 28 (3):033601.
Chicago/Turabian StyleBenjamin Herrmann; Williams Calderón-Muñoz; Eduardo A. Salas; Alejandro Vargas Uscategui; Manuel Duarte-Mermoud; Diego A. Torres. 2016. "Hydrodynamic structure of the boundary layers in a rotating cylindrical cavity with radial inflow." Physics of Fluids 28, no. 3: 033601.
Alejandro Vargas Uscategui; Edgar Mosquera; Boris Chornik; Luis Cifuentes. Electrocatalysis of the hydrogen evolution reaction by rhenium oxides electrodeposited by pulsed-current. Electrochimica Acta 2015, 178, 739 -747.
AMA StyleAlejandro Vargas Uscategui, Edgar Mosquera, Boris Chornik, Luis Cifuentes. Electrocatalysis of the hydrogen evolution reaction by rhenium oxides electrodeposited by pulsed-current. Electrochimica Acta. 2015; 178 ():739-747.
Chicago/Turabian StyleAlejandro Vargas Uscategui; Edgar Mosquera; Boris Chornik; Luis Cifuentes. 2015. "Electrocatalysis of the hydrogen evolution reaction by rhenium oxides electrodeposited by pulsed-current." Electrochimica Acta 178, no. : 739-747.
Alejandro Vargas Uscategui; Edgar Mosquera; Juan M. López-Encarnación; Boris Chornik; Ram S. Katiyar; Luis Cifuentes. Characterization of rhenium compounds obtained by electrochemical synthesis after aging process. Journal of Solid State Chemistry 2014, 220, 17 -21.
AMA StyleAlejandro Vargas Uscategui, Edgar Mosquera, Juan M. López-Encarnación, Boris Chornik, Ram S. Katiyar, Luis Cifuentes. Characterization of rhenium compounds obtained by electrochemical synthesis after aging process. Journal of Solid State Chemistry. 2014; 220 ():17-21.
Chicago/Turabian StyleAlejandro Vargas Uscategui; Edgar Mosquera; Juan M. López-Encarnación; Boris Chornik; Ram S. Katiyar; Luis Cifuentes. 2014. "Characterization of rhenium compounds obtained by electrochemical synthesis after aging process." Journal of Solid State Chemistry 220, no. : 17-21.
Artículo de publicación ISIThis paper presents a study of the in situ production of tantalum carbide nanodispersoids in a copper matrix. The copper matrix composites were produced by means of reactive milling in hexane (C6H14) followed by hot extrusion. The composite materials were characterized by means of optical emission spectroscopy (OES), X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Vickers micro-hardness. The effect of milling time was analyzed in 10, 20 and 30 h in a composite with a nominal composition Cu–5 vol.% TaC. A systematic increase of the dislocations density and the carbon concentration were observed when the milling time was increased, whereas the crystallite size of the composite matrix decreased. The material milled for 30 h and hot-extruded showed a density of 9037 kg m 3 (98.2% densification) and a softening resistance of 204 HV; however the latter value showed an abrupt drop after an annealing treatment at 923 K for 1 h. Finally, the TEM analysis showed the presence of tantalum carbide (Ta4C3) nanodispersoids
Milton Manotas-Albor; Alejandro Vargas-Uscategui; Rodrigo Palma; Edgar Mosquera. In situ production of tantalum carbide nanodispersoids in a copper matrix by reactive milling and hot extrusion. Journal of Alloys and Compounds 2014, 598, 126 -132.
AMA StyleMilton Manotas-Albor, Alejandro Vargas-Uscategui, Rodrigo Palma, Edgar Mosquera. In situ production of tantalum carbide nanodispersoids in a copper matrix by reactive milling and hot extrusion. Journal of Alloys and Compounds. 2014; 598 ():126-132.
Chicago/Turabian StyleMilton Manotas-Albor; Alejandro Vargas-Uscategui; Rodrigo Palma; Edgar Mosquera. 2014. "In situ production of tantalum carbide nanodispersoids in a copper matrix by reactive milling and hot extrusion." Journal of Alloys and Compounds 598, no. : 126-132.
The electrodeposition of rhenium and rhenium oxides from an alkaline aqueous solution containing 0.125 mol dm−3 NH4ReO4 + 0.01 mol dm−3 NaOH (pH 13.3 ± 0.1) has been studied. Cyclic voltammetry studies were carried out using two electrodes, polycrystalline platinum and polycrystalline gold, and the galvanostatic electrodeposition was conducted on a pure copper electrode (99.9%). Information regarding rhenium electrodeposits has been obtained by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results in an alkaline aqueous electrolyte suggest that the electrocrystallization process follows a multi-step mechanism influenced by hydrogen adsorption. The main conclusion was that rhenium, rhenium (IV) oxide and rhenium (VI) oxide coexist in the electrodeposited material.
Alejandro Vargas-Uscategui; Edgar Mosquera; Luis Cifuentes. Analysis of the electrodeposition process of rhenium and rhenium oxides in alkaline aqueous electrolyte. Electrochimica Acta 2013, 109, 283 -290.
AMA StyleAlejandro Vargas-Uscategui, Edgar Mosquera, Luis Cifuentes. Analysis of the electrodeposition process of rhenium and rhenium oxides in alkaline aqueous electrolyte. Electrochimica Acta. 2013; 109 ():283-290.
Chicago/Turabian StyleAlejandro Vargas-Uscategui; Edgar Mosquera; Luis Cifuentes. 2013. "Analysis of the electrodeposition process of rhenium and rhenium oxides in alkaline aqueous electrolyte." Electrochimica Acta 109, no. : 283-290.
In this paper we present a study of electrodeposited nanocrystalline rhenium and rhenium oxides by transmission electron microscopy (TEM). The electrodeposition process was carried out using an alkaline aqueous electrolyte consisting of ammonium perrhenate dissolved in sodium hydroxide solution. The electrodeposited material showed a dendritic structure with no evidence of powder formation at the current density imposed on the system. TEM observations showed that metallic rhenium, rhenium (IV) oxide and rhenium (VI) oxide could coexist in the electrodeposited material.
Alejandro Vargas Uscategui; Edgar Mosquera; Luis Cifuentes. Transmission electron microscopy study of electrodeposited rhenium and rhenium oxides. Materials Letters 2012, 94, 44 -46.
AMA StyleAlejandro Vargas Uscategui, Edgar Mosquera, Luis Cifuentes. Transmission electron microscopy study of electrodeposited rhenium and rhenium oxides. Materials Letters. 2012; 94 ():44-46.
Chicago/Turabian StyleAlejandro Vargas Uscategui; Edgar Mosquera; Luis Cifuentes. 2012. "Transmission electron microscopy study of electrodeposited rhenium and rhenium oxides." Materials Letters 94, no. : 44-46.