摘要
采用第一性原理计算研究了稀土掺杂对Mg-Sc合金马氏体相变的影响和作用机制。结果表明:Y、Gd和Nd原子的d轨道电子增强了Mg和Sc原子间的p-d轨道电子杂化,导致马氏体相对奥氏体的稳定性增强。Y原子的光学振动较强,并与Mg原子和Sc原子的光学振动相互耦合,增强了马氏体的动力学稳定性。Gd或Nd原子推动Mg-Sc声子态密度向声子频率降低的方向平移并且Gd或Nd与Mg和Sc原子的声学振动相互耦合,导致Mg-Sc声学振动显著增强,从而减弱奥氏体和马氏体的动力学稳定性,但奥氏体的减弱程度大于马氏体。因此,Y、Gd和Nd掺杂增大Mg-Sc合金中奥氏体和马氏体的0 K内能差,从而将马氏体相变温度提高至315 K,这优于其他Mg-Sc合金。
The effect and mechanism of rare earth doping on the martensitic transformations of Mg-Sc alloys were investigated via first-principles calculations.The results show that the d-orbital electrons of Y,Gd and Nd atoms enhance the p-d hybridization between Mg and Sc atoms,leading to a strengthening of stability of martensite relative to austenite.The optical vibration of Y atom is strong which couples with the optical vibrations of Mg and Sc atoms,increasing the dynamic stability of martensite.The Gd or Nd atom promotes the shift of Mg-Sc phonon DOS toward the lower phonon frequency,and the acoustic vibration of Gd or Nd atom is coupling with that of Mg and Sc atoms.They cause a significant reinforcement in the acoustic vibration of Mg-Sc,thus weakening the dynamic stabilities of austenite and martensite but the stability reduction of austenite is greater than that of martensite.Accordingly,the doping of Y,Gd and Nd increases the internal energy difference between austenite and martensite at 0 K,thus raising the martensitic transformation temperature up to 315 K,superior to the other Mg-Sc alloys.
作者
李松
金朝晖
袁广银
LI Song;JIN Zhaohui;YUAN Guangyin(School of Materials Sciences and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)
出处
《热加工工艺》
北大核心
2025年第13期99-105,共7页
Hot Working Technology
基金
国家自然科学基金资助项目(52130104,U1804251)
国家重点研发计划项目(2016YFB0701202,2016YFC1102401)
上海交通大学医工交叉基金资助项目(YG2019ZDA02)。
关键词
镁合金
稀土掺杂
相稳定性
马氏体相变
第一性原理计算
magnesium alloys
rare earth doping
phase stability
martensitic transformations
first-principles calculation
