First-principles Study on the Thermodynamic Properties of Nb, Cr2Nb and Nb5Si3 Alloys
Nb-Si-Cr alloys have shown great potential as the aviation materials because of their good mechanical properties and high temperature oxidation resistance.The thermodynamic properties of Nb,Cr2Nb,α-Nb5Si3,β-Nb5Si3,as the main constituent phases of Nb-Si-Cr alloys,were calculated by first-principles methods combined with quasi-harmonic Debye model.The calculated results are in agreement with available experimental data.Compared the thermo-dynamic properties of different phases,it is found that the thermal expansions of these phases are similar and have the same trend with change of temperature.Thermal expansion coefficient of these phases are dependent with increases with temperature and decreases with pressure,respectively,while the bulk moduli decreases with increasing temperature.At last,the micro stress created by the differences in coefficients of thermal expansion between Nb and Cr2Nb upon cooling was evaluated.The result showed that the stress is too small to cause cracking at the interface between Nb and Cr2Nb.
Nb-Si-Cr alloys First-principles Quasi-harmonic Debye model Thermodynamic properties Micro-thermal stress
Zengqian Yang Jiaxiang Shang
School of Materials Science and Engineering, Beihang University, Beijing 100191, China
国际会议
the Chinese Materials Congress 2012(2012年中国材料大会(CMC2012))
太原
英文
466-472
2012-07-13（万方平台首次上网日期，不代表论文的发表时间）