【摘要】 用金相法、电镜观察等研究固溶+时效处理过程中超高氮奥氏体不锈钢氮化物及金属间相析出行为。结果表明:在超高氮奥氏体不锈钢中,随850℃等温时间的延长Cr2N析出过程为:沿晶界链条状析出→沿三晶界交汇处胞状析出并伴随少量的晶内析出→逐渐向晶内生长并与晶内析出相连呈层片状布满整个晶面,Cr2N的析出形态多以颗粒状、蠕虫状、层片状、菊花状分布;随着氮化物的析出伴随有σ相析出,这些金属间相多呈片状出现。探讨了各析出物的析出机理;通过析出物形貌TEM观察和选区衍射分析(SAD)确定了氮化物晶体结构及其与基体的位向关系;氮主要是以Cr2N和过饱和间隙原子的形式存在。更多还原

【Abstract】 The precipitation of nitrides which occurred in solution treatment and aging process of super-high nitrogen austenitic stainless steel was investigated by means of metallography and electron microscopy.The results show that the precipitating process of Cr₂N phase in the stainless steel during isothermal aging is as follows: precipitating as chain-like along grain boundaries→growing as cellular structure from interface of three grains and a small amount of Cr₂N precipitating in grains→growing from grain boundaries into grains gradually and joining to that in grains developing be layered morphology,Cr₂N phase precipitates with various shape such as granular-like,wafer-like,hook-like and lamella-like.With nitrides precipitating,precipitation of σ phases with tablet shape is observed;The crystal structure of precipitated nitride and orientation relationship between the precipitate and the matrix phase was charactorized by TEM observation and SAD analysis.Nitrogen is either to form Cr₂N and or as supersaturated interstitial atoms solid solutioned in matrix phase.更多还原