Article
Materials Science, Multidisciplinary
Chengtao Yu, Qunchang Wang, Minghui Chen, Fuhui Wang
Summary: FGH 97 alloy and its composite with TiC addition were prepared by spark plasma sintering. TiC particles were dissolved into the alloy matrix during ball milling, but precipitated out in-situ as MC solid solution with semi-coherent interface after sintering, resulting in a homogeneous and fine microstructure. After exposure to 900 degrees C for 300 h, the grain size only grew by 31%. The fine microstructure promoted selective oxidation of Al and ensured high oxidation resistance of the composite FT. The precipitated carbides increased oxidation resistance of FT and endowed its oxide scale with self-healing ability for long-term oxidation.
Article
Materials Science, Coatings & Films
Xinlei Pan, Shuangquan Guo, Zeng Tian, Ping Liu, Lei Dou, Xuede Wang, Zhibin An, Liucheng Zhou
Summary: The study shows that laser shock peening technology plays an important role in improving the fatigue resistance of holes, increasing the fatigue limit through the generation of high amplitude compressive residual stress and microhardness, grain refinement, and removal of inclusions. This method is general and flexible, with potential applications to a wide range of engineering components with hole structures.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Chao Li, Jianwei Teng, Biaobiao Yang, Xianjue Ye, Jiantao Liu, Yunping Li
Summary: The novel Co-Ni-based superalloy manufactured by powder metallurgy process exhibited higher mechanical properties compared to the corresponding casting alloy, mainly due to the higher contribution from grain boundary and precipitation strengthening.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Ryo Tamura, Toshio Osada, Kazumi Minagawa, Takuma Kohata, Masashi Hirosawa, Koji Tsuda, Kyoko Kawagishi
Summary: In this study, machine learning-driven optimization was applied to determine promising gas atomization process parameters for the manufacture of Ni-Co based superalloy powders, leading to a substantial increase in yield and a significant reduction in manufacturing cost compared with commercial powders.
MATERIALS & DESIGN
(2021)
Article
Chemistry, Physical
S. D. Gaikwad, Polasani Ajay, Vikram V. Dabhade, S. V. S. Narayana Murty, Sushant Manwatkar, U. Prakash
Summary: In this study, powder forging was used to consolidate a mechanically alloyed Ni-based ODS powder. The forged slab achieved near full density, ultra-fine grain size, and uniform distribution of oxide particles, leading to enhanced mechanical properties at room and elevated temperatures. The powder forging route can serve as an alternative consolidation technique for powder metallurgy ODS superalloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2024)
Article
Chemistry, Multidisciplinary
Iris Carneiro, Jose V. Fernandes, Sonia Simoes
Summary: This study investigated the deformation behavior of aluminium reinforced by carbon nanotubes (Al/CNTs) nanocomposites during cold rolling. Deformation processes after production by conventional powder metallurgy routes can improve the microstructure and mechanical properties by reducing porosity. Metal matrix nanocomposites have great potential in producing advanced components, especially in the mobility industry, with powder metallurgy being one of the most commonly used production processes. Therefore, understanding the deformation behavior of nanocomposites is increasingly important. In this study, nanocomposites were produced via powder metallurgy and advanced characterization techniques were used to examine the microstructure of the powders and nanocomposites. The powder metallurgy route followed by cold rolling is reliable for Al/CNTs nanocomposites. The microstructural characterization revealed that the nanocomposites have a different crystallographic orientation than the Al matrix. CNTs in the matrix influence grain rotation during sintering and deformation. Mechanical characterization showed an initial decrease in hardness and tensile strength for the nanocomposites, which was attributed to the significant Bauschinger effect. The difference in mechanical properties between the nanocomposites and Al matrix was attributed to distinct texture evolution during cold rolling.
Article
Materials Science, Coatings & Films
Ali Khorram
Summary: In the study, nickel-based superalloy Inconel 713 LC was clad with Stellite 31 powder using pulsed Nd:YAG laser, and the influence of laser parameters on the hardness and microstructural features of the clad zones was discussed. The results showed that the clad upper zone consisted of fine coaxial grains and dendrites, the middle part had a homogeneous distribution of coaxial grains, and columnar and coaxial grains were observed at the interface. Increasing heat input resulted in a transformation of coaxial grains into columnar ones, and the formation of cobalt solid solution phase and various carbides in the cladding zone. Increasing laser frequency and pulse width led to enhanced dissolution of the substrate in the cladding zone.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Materials Science, Ceramics
H. Besharatloo, M. de Nicolas-Morillas, M. Chen, A. Mateo, B. Ferrari, E. Gordo, E. Jimenez-Pique, J. M. Wheeler, L. Llanes
Summary: The influence of microstructure and processing route on the mechanical response, deformation, and failure mechanisms of Ti(C,N)-FeNi cermets were investigated by compressing micropillars milled by focused ion beam. Stress-strain curves and deformation mechanisms were observed using scanning electron microscopy. The appropriate micro-pillar size was determined based on the microstructural characteristics to overcome scale effect issues. The results showed a direct relationship between yield strength and ceramic/metal ratio for colloidal samples, and deformation of metallic binder and glide between Ti(C,N)/Ti(C,N) particles were dominant mechanisms during compression.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Arman Khobzi, Mandana Adeli, Ashkan Sabour-Bagherzadeh, Ashkan Arab, Hooman Abedi
Summary: NiTi intermetallic compound was successfully fabricated through combustion synthesis processes, with the combustion mode and Ni particle size affecting the microstructure and microhardness of the final products. The results showed that samples produced by thermal explosion had coarse dendrites and higher microhardness values, while those synthesized by self-propagating process exhibited microstructures similar to heat-treated NiTi. Decreasing Ni particle size had a grain refining effect on NiTi2 in both modes.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Paula Rodriguez-Gonzalez, Miguel Angel Monge, Elena Gordo, Elisa Maria Ruiz-Navas
Summary: This study investigates the influence of alloying elements in Al-Cu-Li alloys rods produced by novel powder metallurgy routes. Two different methods were used to prepare 5mm diameter rods, and they were characterized by SEM, EBSD, Vickers microhardness, chemical composition (ICP-OES), and tensile tests. The results show that alloy 1 (AA2060) has a more homogeneous microstructure than alloy 2 (AA2196), and the addition of Mg improves the microstructure after heat treatment.
MATERIALS CHARACTERIZATION
(2023)
Article
Chemistry, Physical
Jian Jia, Yiwen Zhang, Yu Tao, Ting Yan, Hongyan Ji
Summary: The effects of solution temperature on a novel high gamma ' volume fraction P/M superalloy were investigated. The results showed that a higher solution temperature could decrease the size of gamma ' precipitates and enhance the strength of the alloy.
Article
Nanoscience & Nanotechnology
X. Yao, Q. Ding, X. Zhao, X. Wei, J. Wang, Z. Zhang, H. Bei
Summary: The study shows that the gamma/gamma' two-phase cuboid microstructure of SX superalloys can be restored by solid solution plus aging treatment, but additional recovery annealing is required for compressed alloys to prevent recrystallization. Defect analysis in nanometer scales justifies the mechanism behind the additional recovery annealing.
MATERIALS TODAY NANO
(2022)
Article
Chemistry, Physical
Chengtao Yu, Yu Zhen, Jing Zhao, Qunchang Wang, Jinlong Wang, Minghui Chen, Fuhui Wang
Summary: A Ni-based superalloy composite (FTSC) was successfully prepared by spark plasma sintering with Ti3SiC2 (15 vol %) and FGH97 alloy powders as precursors. During sintering, the weakly bonded Si layers de-intercalate from Ti3SiC2 and the remaining TiC is eroded by the elements of the matrix, which promoted in-situ precipitation of MC and M6C carbides. The Zener pinning effect of ultra-fine duplex carbides results in refinement of alloy grains and notably improvement in mechanical strength. Comparing to the alloy FGH97, the composite FTSC possesses 55% higher microhardness, 100% higher compressive yield strength and 92% higher flexural strength. The refined grains ensured fast formation of a protective alumina scale at surface, which provides high oxidation resistance for the composite.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Zijun Qin, Weifu Li, Zi Wang, Junlong Pan, Zexin Wang, Zihang Li, Guowei Wang, Jun Pan, Feng Liu, Lan Huang, Liming Tan, Lina Zhang, Hua Han, Hong Chen, Liang Jiang
Summary: In this study, a database of γ' precipitation was established by integrating high-throughput experiments and image recognition technology. A high-confidence prediction model was developed to accurately predict the relevant parameters of γ' precipitation in different alloys.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Alireza Dareh Baghi, Shahrooz Nafisi, Heike Ebendorff-Heidepriem, Reza Ghomashchi
Summary: A detailed study comparing the microstructural differences between Ti-6Al-4V parts fabricated via conventional powder metallurgy and laser powder bed fusion routes revealed that L-PBF parts have a higher microhardness with a single phase of martensitic alpha '. On the other hand, parts sintered via powder metallurgy showed two phases with lower microhardness. The rapid cooling of the beta phase had no effect on the hardening of the bulk martensitic hcp alpha ' in L-PBF parts.
Article
Materials Science, Multidisciplinary
Ian N. Bakst, John T. Sypek, Sriram Vijayan, Shuyang Xiao, Mark Aindow, Seok-Woo Lee, Christopher R. Weinberger
Summary: In this study, DFT simulations combined with analytical models were used to investigate the impact of defects and temperature on the mechanical response of [001]-oriented compression of CaFe2As2. The experiments showed that the solution in which CaFe2As2 is grown and post-growth heat treatment can affect the mechanical response of the materials. The simulations revealed that FeAs and Fe precipitate out of Fe-rich CaFe2As2, influencing the actual precipitates with the formation of a low-energy coherent interface.
Article
Materials Science, Multidisciplinary
John T. Sypek, Sriram Vijayan, Ian Bakst, Shuyang Xiao, Matthew J. Kramer, Paul C. Canfield, Mark Aindow, Christopher R. Weinberger, Seok-Woo Lee
Summary: The micropillar compression experiments on [001]-oriented CaFe2As2 single crystals have shown the existence of superelasticity with a high elastic limit. The collapsed tetragonal phase transition, influenced by microstructure and temperature, is the main mechanism of superelasticity. Factors like vacancies and nanoprecipitates affect the mechanical behavior significantly, and the onset stress for the phase transition decreases with decreasing temperature.
Article
Materials Science, Multidisciplinary
H. R. Leonard, S. Rommel, M. X. Li, S. Vijayan, T. J. Watson, T. Policandriotes, M. Aindow
Summary: The thermal behavior of a powder-processed Al-Cr-Mn-Co-Zr alloy was studied, revealing that the alloy hardened around 400 degrees Celsius during heat treatment and then softened significantly at higher temperatures. The main microstructural change was the precipitation of a ternary Al11(Cr,Mn)2 phase within the Al matrix.
MATERIALS CHARACTERIZATION
(2021)
Article
Engineering, Manufacturing
Rainer J. Hebert, Yu Sun, Mark Aindow, Edward J. Garboczi
Summary: By using XCT and mathematical analysis, this study conducted 3D characterization of five titanium alloy powders, revealing differences between powders and the partial orientation issue of particle projections generated by the DIA instrument.
ADDITIVE MANUFACTURING
(2021)
Article
Materials Science, Multidisciplinary
H. R. Leonard, S. Rommel, M. X. Li, M. E. Krug, T. J. Watson, T. Policandriotes, M. Aindow
Summary: The thermal stability and decomposition products of the quasicrystalline I-phase in a powder-processed Al-2.8Cr1.51Mn-0.28Co-0.31Zr alloy were studied, revealing that the I-phase decomposed into Al45(Cr,Mn)7 phase before transforming into an Al12(Cr,Mn) phase with a coarse irregular morphology during heat treatment. The study provides insights into the processing and operating conditions for quasicrystal-reinforced Al alloys.
MATERIALS CHARACTERIZATION
(2021)
Article
Chemistry, Multidisciplinary
Shuyang Xiao, Vladislav Borisov, Guilherme Gorgen-Lesseux, Sarshad Rommel, Gyuho Song, Jessica M. Maita, Mark Aindow, Roser Valenti, Paul C. Canfield, Seok-Woo Lee
Summary: Most crystalline solids have a maximum recoverable strain of less than 1%, but this study shows that a SrNi2P2 micropillar exhibits pseudoelasticity with a large maximum recoverable strain of 14% via a unique double lattice collapse-expansion mechanism. This new class of high-performance ThCr2Si2-structured materials could lead to new research opportunities in the field of pseudoelasticity.
Article
Chemistry, Applied
Hande Gunes, Deniz Sanli Yildiz, Barkin Ozener, Gokhan Hisar, Sarshad Rommel, Mark Aindow, Selmi Erim Bozbag, Can Erkey
Summary: Pt/Al2O3 and PtPd/Al2O3 catalysts prepared via supercritical deposition method using supercritical carbon dioxide showed good catalytic activity for NO and C3H6 oxidation and C3H6-SCR reactions. Particle size and activity were affected by Pt loading and Pd addition.
Article
Materials Science, Coatings & Films
A. A. Hemeda, A. Mishra, J. Xu, C. T. Wu, D. Cote, M. Siopis, I. M. Nault, V. K. Champagne, S-W Lee, M. Aindow, A. Nardi, J. W. Palko, Y. Ma
Summary: In this paper, the micromechanical performance of Al6061 single-particle deposition by a cold spray process is studied using an axisymmetric smoothed particle hydrodynamic approach. The study shows that the yield strength at the particle-substrate interface is two to three times greater than that in the bulk, and there are heterogeneous mechanical properties in the splat and along the splat-substrate interface.
JOURNAL OF THERMAL SPRAY TECHNOLOGY
(2022)
Article
Chemistry, Physical
Phillimon Modisha, Rudaviro Garidzirai, Hande Gunes, Selmi Erim Bozbag, Sarshad Rommel, Erdal Uzunlar, Mark Aindow, Can Erkey, Dmitri Bessarabov
Summary: Pt/Al2O3 catalysts prepared using the SCD method showed the best catalytic performance for the dehydrogenation of H18-DBT, attributed to the higher dispersion of Pt particles and smaller particle size. The deactivation was mainly caused by adsorbed H0-DBT blocking the active sites. The study revealed that improved catalyst performance led to increased production of liquid by-products and carbon materials.
Article
Engineering, Manufacturing
M. X. Li, H. R. Leonard, S. Rommel, C. Hung, T. J. Watson, T. Policandriotes, R. J. Hebert, M. Aindow
Summary: Evaluation of a powder-processed Al-Cr-Mn-Co-Zr alloy for metal additive manufacturing (MAM) using laser glazing method shows promising results with regards to microstructure and mechanical properties of the laser tracks.
ADDITIVE MANUFACTURING
(2022)
Article
Electrochemistry
Sansim Bengisu Barim, Grigorios Raptapoulos, Sarshad Rommel, Mark Aindow, Patrina Paraskevopoulou, Can Erkey
Summary: We synthesized carbon aerogel supported Pt nanoparticles as electrocatalysts for the oxygen reduction reaction using the super-critical CO2 deposition technique. By controlling the pore structure of the carbon aerogel and the initial Pt nanoparticle size, we achieved highly active and stable electrocatalysts.
ELECTROCHIMICA ACTA
(2022)
Article
Materials Science, Multidisciplinary
S. Rommel, H. R. Leonard, M. X. Li, T. J. Watson, T. Policandriotes, M. Aindow
Summary: The impact of surface corrosion product layers on the pitting corrosion behavior of three Al-Cr-Mn-Co-Zr alloys has been studied. The study found that the corrosion product bilayer can improve the resistance of the alloys to pitting corrosion.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Baris Yavas, Cain J. Hung, Sanjeev K. Nayak, Mark Aindow, S. Pamir Alpay
Summary: This study employs density functional theory to analyze the statistically generated ground states of orthorhombic approximants in Al81Cu7Fe4Cr8 alloy, shedding light on the role of elemental variations. Results show that the stability of QC approximants is strongly dependent on the specific locations of Cu and Cr atoms, and the icosahedral phase is more favorable than the decagonal phase.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Shuyang Xiao, Sarshad Rommel, Kiera A. A. Burns, Aurora A. A. Buswell, Vladislav Borisov, Juan Schmidt, Roser Valenti, Paul C. C. Canfield, Mark Aindow, Seok-Woo Lee
Summary: Nanoindentation was performed on SrNi2P2 single crystals and their dilute solid solutions to investigate the effects of elemental doping on Young's modulus and dislocation nucleation stress. The results showed that Young's modulus and the dislocation nucleation stress decreased as the Rh content increased, with their dependence on Rh content varying. The main reasons for this decrease were identified as a local structural transition and local compressive residual stresses. The results also indicated that elemental doping may not necessarily strengthen materials controlled by dislocation nucleation.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Nanoscience & Nanotechnology
Baris Yavas, Cain J. Hung, Mingxuan Li, Rainer J. Hebert, S. Pamir Alpay, Mark Aindow
Summary: Laser glazing in a powder bed fusion instrument was used to evaluate the microstructure of an Al85Cu6Fe3Cr6 alloy, revealing the presence of I-phase quasicrystals, Al2Cu, and FCC Al. Laser tracks produced under different conditions showed a fine and uniform phase mixture with over 70% I-phase, a thin film of Al2Cu, and no cracking or macrosegregation. The reasons for the formation of I-phase instead of the previously reported D-phase in this alloy were discussed.
SCRIPTA MATERIALIA
(2023)
