TY - JOUR
T1 - Mechanical properties of refractory high-entropy alloys
T2 - Experiments and modeling
AU - Yao, H. W.
AU - Qiao, J. W.
AU - Hawk, J. A.
AU - Zhou, H. F.
AU - Chen, M. W.
AU - Gao, M. C.
N1 - Funding Information:
The authors would like to acknowledge the financial support of National Natural Science Foundation of China (Nos. 51371122 and 51501123 ), the Youth Natural Science Foundation of Shanxi Province, China (Nos. 2015021005 and 2015021006 ), and the financial support from State Key Lab of Advanced Metals and Materials (Nos. 2015-Z07 and 2016-ZD03 ). The DFT and CALPHAD modeling work were carried out to support the Cross-Cutting Technologies Program at the National Energy Technology Laboratory (NETL) – Strategic Center for Coal, managed by Robert Romanosky (Technology Manager) and Charles Miller (Technology Monitor). The Research was executed through NETL's Office of Research and Development's Innovative Process Technologies (IPT) Field Work Proposal. Research performed by AECOM Staff was conducted under the RES contract DE-FE-0004000.
Funding Information:
The computational modeling work presented in the paper is project was funded by the Department of Energy, National Energy Technology Laboratory, an agency of the United States Government, through a support contract with AECOM. Neither the United States Government nor any agency thereof, nor any of their employees, nor AECOM, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2017
Y1 - 2017
N2 - Refractory high-entropy alloys hold the potential for high-temperature applications beyond the capability of the state-of-the-art Ni-based superalloys, and thus, it is important to study their solid solution formation characteristics and mechanical properties. In this study, designed by CALPHAD method, formation of as-cast arc-melted body-centered cubic MoNbTaTiV was experimentally verified using X-ray diffraction and scanning electron microscopy. The measured density and lattice parameter for MoNbTaTiV are 9.29g/cm3and 3.224 Å, which obey the rule of mixtures (ROM). The alloy exhibits high hardness at 443 Hv, high yield strength at 1.4 GPa, and good compressive fracture strength at 2.45 GPa with a fracture strain of ∼30% at room temperature. The yield strength and hardness values of this alloy, and other single-phase refractory high-entropy alloys, are estimated using a simple model of solid solution strengthening. Reasonable agreement between modeling prediction and experiments is obtained. In addition, first-principles density functional theory calculations predict an enthalpy of formation of −0.865 kJ/mol for the MoNbTaTiV alloy, with calculated atomic volume and elastic properties (e.g., bulk and elastic moduli) obeying the ROM.
AB - Refractory high-entropy alloys hold the potential for high-temperature applications beyond the capability of the state-of-the-art Ni-based superalloys, and thus, it is important to study their solid solution formation characteristics and mechanical properties. In this study, designed by CALPHAD method, formation of as-cast arc-melted body-centered cubic MoNbTaTiV was experimentally verified using X-ray diffraction and scanning electron microscopy. The measured density and lattice parameter for MoNbTaTiV are 9.29g/cm3and 3.224 Å, which obey the rule of mixtures (ROM). The alloy exhibits high hardness at 443 Hv, high yield strength at 1.4 GPa, and good compressive fracture strength at 2.45 GPa with a fracture strain of ∼30% at room temperature. The yield strength and hardness values of this alloy, and other single-phase refractory high-entropy alloys, are estimated using a simple model of solid solution strengthening. Reasonable agreement between modeling prediction and experiments is obtained. In addition, first-principles density functional theory calculations predict an enthalpy of formation of −0.865 kJ/mol for the MoNbTaTiV alloy, with calculated atomic volume and elastic properties (e.g., bulk and elastic moduli) obeying the ROM.
KW - CALPHAD
KW - First-principles
KW - High-entropy alloy
KW - Mechanical properties
KW - Rule of mixtures
KW - Solid solution strengthening
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U2 - 10.1016/j.jallcom.2016.11.188
DO - 10.1016/j.jallcom.2016.11.188
M3 - Article
AN - SCOPUS:85006134412
VL - 696
SP - 1139
EP - 1150
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
ER -