SDCM1新型热作模具钢回火过程中碳扩散行为的电阻表征  

Characterization of carbon diffusion behaviors of SDCM1 new hot working die steel during tempering by in-situ resistance method

作　　者：张进峰 吴晓春[1,2,3] 闵娜[1,2] ZHANG Jin-feng;WU Xiao-chun;MIN Na(School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai 200072,China;State Key Laboratory of Advanced Special Steel,Shanghai 200072,China;School of Electronie and Information Engineering,Suzhou V ocational University,Suzhou 215104,China)

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]上海市钢铁冶金新技术开发应用重点实验室,上海200072 [3]高品质特殊钢冶金与制备国家重点实验室,上海200072 [4]苏州市职业大学电子信息工程学院,江苏苏州215104

出　　处：《材料热处理学报》2021年第5期88-95,共8页Transactions of Materials and Heat Treatment

基　　金：国家重点研发计划(2016YFB0300400);苏州市职业大学科研平台(201804000050)。

摘　　要：采用原位电阻法,并结合硬度测量、微观组织分析技术对SDCM1新型热作模具钢从室温至590℃回火过程中的碳原子扩散行为进行了研究。结果表明:在80℃至125℃回火时,试验钢的电阻偏离线性出现下降趋势,同时硬度出现峰值,这主要是由于碳原子向位错扩散所致,其激活能为83 kJ·mol^(-1);180~250℃回火时,电阻偏离线性略微降低,归因于ε碳化物的形核;300℃以上回火时,电阻随温度升高增势减缓,结合透射电镜(TEM)分析,这主要是由于碳化物的析出所致,通过电阻的不同演化趋势可以判断碳化物和合金碳化物的析出差异;温度升高至590℃等温时,试验钢的电阻急剧下降,这主要是由于等温碳化物的大量析出所致。研究表明电阻法可以清晰表征模具钢的回火过程中碳原子运动、占位及组织演化特征与动力学过程,是一种有效的研究手段。The diffusion behavior of carbon atoms of SDCM1 new hot working die steel during tempering from room temperature to 590 ℃ was studied by using the resistance method, combined with the hardness measurementand microstructure analysis. The results show that during tempering at 80-125 ℃, the resistance deviation from linearly of the experimental steel decreases, the hardness reaches peak value, this is mainly due to the diffusion of carbon atoms to dislocations, and the activation energy of the steel is 83 kJ·mol^(-1). During tempering at 180-250 ℃, the resistance deviation from linearly decreases slightly, this is mainly due to the nucleation of ε carbides. During tempering at above 300 ℃, the resistance increases slowly with the increase of temperature, combined with transmission electron microscopy(TEM) analysis, this is mainly due to the precipitation of carbides, the precipitation difference between Fe3C carbide and alloy carbides can be judged by different evolution trend of resistance. When the tempering temperature increases to 590 ℃, the resistance of the experimental steel decreases sharply, this is mainly due to the large precipitation of isothermal carbides. The results show that the resistance method can clearly characterize the movement, occupation, microstructure evolution and dynamics of carbon atoms of the SDCM1 new hot working die steel during tempering, is an effective means of research.

关 键 词：热作模具钢 碳扩散 电阻 偏聚 析出 

分 类 号：TG142.4[一般工业技术—材料科学与工程]