Mo对B2-NiAl力学性质影响的第一原理计算  

First-principles calculation on the effects of Mo addition on mechanical properties of B2-NiAl

作　　者：陈律[1] 李敏 刘逸众[1] CHEN Lü;LI Min;LIU Yizhong(Aviation Electromechanical Equipment Maintenance Department,Air Force Institute of Aeronautical Maintenance Technology,Changsha 410124,China)

机构地区：[1]空军航空维修技术学院航空机电设备维修学院,湖南长沙410124

出　　处：《兵器材料科学与工程》2020年第3期64-69,共6页Ordnance Material Science and Engineering

基　　金：湖南省自然科学基金科教联合基金(2017JJ5057)。

摘　　要：采用第一性原理赝势平面波方法,基于虚拟晶体势函数近似(VCA),研究不同Mo合金化浓度(原子数分数为0~3.2%)对B2-NiAl晶体C44、Cauchy压力参数、弹性模量E、切变模量G及G/B0比值的影响。结果表明:无论是理想NiAl晶体,还是含Ni空位或Ni反位的NiAl缺陷晶体,x<3.2%的Mo合金化均可降低其弹性模量E、切变模量G;随Mo合金化的原子数分数提高到3.2%,NiAl晶体材料的G/B0比值逐步降低,且在x=3.2%时效果最明显;NiAl合金中点缺陷的存在不但未影响Mo对NiAl晶体G/B0比值的降低,反而弥补了由于Mo合金化的原子数分数低于1.4%而不能降低NiAl晶体G/B0比值的不足。电子态密度显示,Mo原子能协同B2-NiAl晶体中的点缺陷削弱Ni(d)-Ni(d)主要成键峰的杂化效应,降低主要成键峰的方向性。The effects of Mo alloying concentration(x=0-3.2%,atom fraction) on several parameters such as elastic constant C44,Cauchy pressure,Elastic modulus E,the shear modulus G and their ratio G/B0 of B2-NiAl supercells with or without point defect were calculated in the framework of virtual crystal approximation by the first-principles pseudopotential plane-wave method.The results show that Mo addition with x<3.2% is proved to reduce the elastic modulus E and the shear modulus G of NiAl intermetallic compounds either for perfect or defect crystals.With the increasing of Mo alloying concentration from 0 to 3.2%,the G/B0 ratio of NiAl crystal material decreases gradually,especially at x is 3.2%.The existence of point defects in NiAl alloy not only has no effect on the decrease of G/B0 ratio of NiAl crystal,but also makes up the deficiency that the G/B0 ratio of NiAl crystal can not be reduced because the Mo alloying concentration is less than 1.4%.Mo atoms can cooperate with the point defects in B2-NiAl crystal to weaken the hybridization effect of the main bonding peaks of Ni(d)-Ni(d) and to decrease the directivity of the main bonding peaks.

关 键 词：B2-NiAl Mo合金化 VCA近似 弹性性质 

分 类 号：TG146.2[一般工业技术—材料科学与工程]