Two new quaternary Cr_(x)Ti_(0.75)Mo_(0.75)V_(1.5−x)AlC_(2)(x=1.25 and 1)MAXs and Cr_(0.75)Ti_(0.75)Mo_(0.75)V_(0.75)AlC_(2) are synthesized via hot pressing.An unprecedented transition in M-site atomic occupancy from...Two new quaternary Cr_(x)Ti_(0.75)Mo_(0.75)V_(1.5−x)AlC_(2)(x=1.25 and 1)MAXs and Cr_(0.75)Ti_(0.75)Mo_(0.75)V_(0.75)AlC_(2) are synthesized via hot pressing.An unprecedented transition in M-site atomic occupancy from out-of-plane order to solid solution is observed along with composition variation,which also increases the configurational entropy from medium-to high-entropy.Through experimental observations and theoretical calculations,the influence of the atomic distribution on the material properties is analyzed.Eventually,an approximately 40%increase in the Vickers hardness compared with that of Cr_(2)TiAlC_(2) and a low thermal conductivity are detected for the three MAXs,which can be attributed to the solid solution strengthening effects and the enhanced scattering of both electrons and phonons from the high-entropy structure.展开更多
基金grateful for the financial support from the National Natural Science Foundation of China(No.52275212)the“Special Lubrication and Sealing for Aerospace”Shaanxi Provincial Science and Technology Innovation Team(No.2024RSCXTD-63)+2 种基金the Fundamental Research Funds for the Central Universities(No.D5000230047)the Aeronautical Science Foundation of China(2024Z046053001)The authors thank the support and expert advice of Professor Zhang Qichun's group(City University of Hong Kong)on the calculations.
文摘Two new quaternary Cr_(x)Ti_(0.75)Mo_(0.75)V_(1.5−x)AlC_(2)(x=1.25 and 1)MAXs and Cr_(0.75)Ti_(0.75)Mo_(0.75)V_(0.75)AlC_(2) are synthesized via hot pressing.An unprecedented transition in M-site atomic occupancy from out-of-plane order to solid solution is observed along with composition variation,which also increases the configurational entropy from medium-to high-entropy.Through experimental observations and theoretical calculations,the influence of the atomic distribution on the material properties is analyzed.Eventually,an approximately 40%increase in the Vickers hardness compared with that of Cr_(2)TiAlC_(2) and a low thermal conductivity are detected for the three MAXs,which can be attributed to the solid solution strengthening effects and the enhanced scattering of both electrons and phonons from the high-entropy structure.
