超高碳钢中的显微偏析  

MICRO SEGREGATION IN ULTRA HIGH CARBON STEEL

作　　者：林一坚[1,2] 王军[3,2] 章靖国[2,3] 

机构地区：[1]上海远程教育集团,上海200080 [2]上海市金属功能材料重点实验室 [3]同济大学材料科学与工程学院

出　　处：《上海金属》2009年第1期1-5,共5页Shanghai Metals

摘　　要：对比研究了超高碳钢1.8C-1.6Al-1.5Cr-0.5Mn-余Fe(wt%)喷射成形坯件与其母合金的显微偏析情况,发现快速凝固不仅可以减少偏析程度,而且可以改变偏析性质,使常规凝固下呈反偏析的Al变为正偏析。此现象可用碳的偏析程度影响其它溶质元素在液固相中的活度对比来说明。另外还发现,快速凝固可形成含Al且碳缺位的非平衡渗碳体,加热至共析转变温度,可很快转变为含富Al铁素体区的"孔洞状渗碳体"。The micro segregation in ultra high carbon steel with 1.8C-1.6Al-1.5Cr-0.5Mn （wt%） was studied by comparing spray-formed and conventionally cast specimens. It was found that rapid solidification could not only lessen segregation but also change segregation nature, namely, Al showed negative segregation in normal solidification but positive segregation in rapid solidification. This phenomenon could be explained based on the fact that different degree of carbon segregation could influence activity contrast of other solute between in liquid and in solid. Besides, it was also found that non-equilibrium cementite containing Al atoms and carbon-vacancies could form during rapid solidification, which would soon turn to ＂ porous cementite＂ when heated to eutectoid reaction temperature.

关 键 词：超高碳钢 喷射成形 偏析 快速凝固 渗碳体 

分 类 号：TG111.4[金属学及工艺—物理冶金] TG142[金属学及工艺—金属学]