摘要
采用硬度和扫描组织评价方法分析了三种Fe-Cr-Mo-W-V热作模具钢(DM、H21和H13)在580~650℃下的热稳定性,研究结果表明DM钢较H21、H13钢具有高的热稳定性。同时,通过测定三种钢的连续加热曲线并结合透射电镜组织,研究了高温热稳保温过程中存在的重要碳化物的类型。为了揭示Fe-Cr-Mo-W-V钢的热稳定机理,计算了三种钢由M2C型碳化物形成阶段向MC型碳化物形成阶段转变的临界点激活能,其值为163.9~204.1kJ/mol,表明M2C、MC型碳化物的形成不仅受体扩散影响,而且与位错管道扩散激活能相关,DM钢具有最高临界激活能,其值高达204.1kJ/mol。进一步对比三种钢中的价电子结构差异,得出最高热稳定性的DM钢具有最佳价电子结构。
Three kinds of Fe-Cr-Mo-W-V hot working die steels(DM,H21 and H13)were prepared to investigate the thermal stability at 580-650℃.Utilizing the hardness measurement and scanning electron microscopy(SEM),an attempt was made to study the thermal stability of three hot working die steels.The results indicated that DM steel had a higher thermal stability than H21 and H13 steels during tempering.Besides,combined with transmission electron microscopy(TEM),the dilatometric data(conti-nuous heating transformation curves)during tempering were analyzed to determine the significance carbides resulting in high thermal stability in Fe-Cr-Mo-W-V steels.To improve the understanding of the thermal stability mechanism,the activation energy of the transformation of MC carbides from M 2C carbides in DM,H21 and H13 steels were determined as 163.9-204.1 kJ/mol,which reflect the diffusion of the solute atoms in the transformation reaction of M 2C and MC carbides is controlled by volume diffusion and dislocation pipe diffusion,DM steel own the highest activation energy as 204.1 kJ/mol.Furthermore,comparing the differences of the value electron structures in three steels,DM steel with excellent thermal stability shows the best electron structure.
作者
施渊吉
吴晓春
闵娜
SHI Yuanji;WU Xiaochun;MIN Na(School of Materials Science and Engineering,Shanghai University,Shanghai 200072)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2018年第6期930-936,956,共8页
Materials Reports
基金
国家重点研发计划(2016YFB0300400)
关键词
热稳定性
热作模具钢
连续加热析出曲线
价电子理论
thermal stability
hot working die steel
continuous heating transformation curve
electron structure
