Ni_(75)Al_(21.5)Ti_(3.5)合金时效行为的微观相场计算  

Microscopic phase-field calculate on aging behavior of Ni_(75)Al_(21.5)Ti_(3.5) alloy

作　　者：赵彦[1] 陈铮[1,2] 张济祥[1] 王永欣[1] 张利鹏[1] 

机构地区：[1]西北工业大学材料科学与工程学院,陕西西安710072 [2]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《材料热处理学报》2009年第3期192-197,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金项目(50671084);国家高技术发展计划项项目(2002AA331050)

摘　　要：应用微观相场方法计算了Ni75Al21.5Ti3.5合金873K时效时的沉淀行为。利用原子演化图、长程序参数和成分序参数的演化、有序相颗粒的平均直径、颗粒数目及合金原子在α、β位置占位几率的演化等研究手段,讨论了Al、Ti原子的有序化和原子簇聚过程;有序相的形核机制及粗化行为;原子的择优占位行为。结果表明:有序相颗粒的形核机制为失稳分解机制,Al原子基本达到有序排列,同时存在Ni-Al原子反位,Ti原子未达到完全有序排列,在γ′有序相中择优占据Al位,且有序相生成过程中,前期的生长动力学指数为1/2,后期的生长动力学指数为2/5。The aging behavior of Ni75Al21.5Ti3.5 alloy at 873K was studied by microscopic phase-field model. Based on the analysis ot atom figures, the average diameters and number of order phase, and the evolution of atom occupied probabilities, the problems about the ordering and cluster of Al and Ti, the nucleation mechanism of ordered phases, coarsening behavior, and atom preferential occupation were investigated. The results show that the nucleation mechanism of order phase is spinodal deeomposition, and the final order degree of Al atoms approximates 1 which also accompanies the Ni-Al anti-site. Ti atoms don＇ t reach ordering wholly and prefer to occupy Al site. During the growth of order phase, the dynamic exponent of the particles coarsening approaches 1/2 at the early stage, but fails to 2/5 at the late stage.

关 键 词：Ni75Al21.5Ti3.5合金 时效行为 微观相场方法 

分 类 号：TG162.83[金属学及工艺—热处理] TG146.1[金属学及工艺—金属学]