Guili LIU
,
Rongde LI
,
Zhenping ZHOU
材料科学技术（英文）
A model of liquid ZA27 cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent α phase and liquid is also presented by means of computer programming. Recursion method is adopted to calculate the electronic structure of RE (rare earth) in grains and around phase boundaries respectively. The calculation shows that RE is more stable around phase boundaries than in grains, which explains the fact that the solution of RE inα phase is less, and RE mainly aggregates in front of phase boundary. The calculations of bonding order integrals also show that RE in front of phases hardly solidify onto the grain surfaces as active element so as to prevent grains growth and refine the grains. As a result, the modification mechanism of RE may be explained from the view of electronic structure.
关键词:
Atomic structural model
,
null
,
null
刘贵立
金属学报
采用计算机模拟技术创建钛α相和β相晶粒、α相中 刃位错及位错塞积形成的微裂纹原子集团模型。利用递归法（Recursion）计算了位错、裂纹及α相晶粒的电子结构（费米能级、结构能、环境敏感镶嵌能等），计算并分析了合金元素Mo、V对β相原子结合能的影响。结果表明：氢在位错处的环境敏感镶嵌能较低，易于在位错处聚积，形成氢原子气团。位错对氢原子气团的“钉扎”作用使钛合金局部硬化，使位错运动受阻塞积形成微裂纹。裂纹尖端费米能级高于裂纹其他区域，电子从裂纹尖端流向裂纹其他区域造成电位差，在电解质作用下裂纹尖端阳极分解腐蚀。拉应力与裂纹处的氢气压使裂纹解理或沿晶延伸，促进应力腐蚀的发展。合金元素Mo、V有利于α钛合金中β相的形成，阻止裂纹在α相中扩展，提高合金应力腐蚀抗力。
关键词:
递归法
,
,
electronic structure
