Ni segregation and thermal stability of reversed austenite in a Fe–Ni alloy processed by QLT heat treatment  

作　　者：Tao Pan Jing Zhu Hang Su Cai-Fu Yang 

机构地区：[1]Division of Structural Materials, Central Iron and Steel Research Institute [2]School of Materials Science and Engineering, Tsinghua University

出　　处：《Rare Metals》2015年第11期776-782,共7页稀有金属（英文版）

基　　金：financially supported by the National High Technology Research and Development Program of China (No. 2007AA03Z506);the National Basic Research Program of China (No. 2015CB654803)

摘　　要：High-resolution transmission electron microscopy(HRTEM) and X-ray diffraction(XRD) were used to investigate Ni segregation and thermal stability of reversed austenite(RA) in a Fe–Ni alloy processed by quench–lamellarize–temper(QLT) heat treatment. The results show that the 77 K impact energy of the alloy increases with RA content increasing. As an austenite-stabilizing element, Ni is found to segregate in RA, though Ni is not evenly distributed within RA. The amount of segregations increases near the boundary(twice as high as the balanced content)and decreases to some extent in the center of the RA regions. Ni concentration in matrix near the boundary is lower than that in matrix far from the boundary because of Ni atom transportation from a to c near the boundary. RA in this alloy has high heat and mechanical stability but is likely to lose its stability and transform to martensite when a mechanical load is applied at ultralow temperatures(77 K), which induces plasticity.High-resolution transmission electron microscopy(HRTEM) and X-ray diffraction(XRD) were used to investigate Ni segregation and thermal stability of reversed austenite(RA) in a Fe–Ni alloy processed by quench–lamellarize–temper(QLT) heat treatment. The results show that the 77 K impact energy of the alloy increases with RA content increasing. As an austenite-stabilizing element, Ni is found to segregate in RA, though Ni is not evenly distributed within RA. The amount of segregations increases near the boundary(twice as high as the balanced content)and decreases to some extent in the center of the RA regions. Ni concentration in matrix near the boundary is lower than that in matrix far from the boundary because of Ni atom transportation from a to c near the boundary. RA in this alloy has high heat and mechanical stability but is likely to lose its stability and transform to martensite when a mechanical load is applied at ultralow temperatures(77 K), which induces plasticity.

关 键 词：Reversed austenite Quench–lamellarize–temper Compo 

分 类 号：TG156[金属学及工艺—热处理] TG141[金属学及工艺—金属学]