钼含量对粉末烧结钢微观组织和压缩流变致密化的影响  

Effects of molybdenum content on the microstructure,flow and densification behaviors of powder sintered steel during compaction

作　　者：张召 郭彪[1] 周张健[2] 简杰 王兴贵 冉潮流 宋久鹏 敖进清[1] ZHANG Zhao;CUO Biao;ZHOU Zhangjian;JIAN Jie;WANG Xinggui;RAN Chaoliu;SONG Jiupeng;AO Jinqing(School of Materials Science and Engineering,Xihua University,Chengdu 610039,China;School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Sichuan Yuteng Machinery Forging Co.,Ltd.,Guang'an 638500,China)

机构地区：[1]西华大学材料科学与工程学院,成都610039 [2]北京科技大学材料科学与工程学院,北京100083 [3]四川渝腾机械锻造有限公司,四川广安638500

出　　处：《材料科学与工艺》2024年第5期26-33,共8页Materials Science and Technology

基　　金：国家自然科学基金资助项目(52274368,51504197);四川省科技厅重点研发计划项目(2022YFG0346).

摘　　要：为了研究钼含量对粉末烧结钢微观组织和压缩流变致密化的影响,采用万能试验机对不同钼含量的粉末烧结钢进行压缩实验,并观察不同钼含量粉末烧结钢的微观组织,分析其压缩缩过程流变应力的变化规律,以及晶粒和孔隙的变形特点。结果表明:随着钼含量的增加,微观组织中珠光体和铁素体逐渐减少,贝氏体逐渐增加,且钼含量达到0.85%时组织中主要为细小贝氏体;粉末烧结钢压缩流变过程基本遵循抛物线式应变硬化规律,随着钼含量增加,强度不断增大,极限应变量不断减小;在同一应变下的应变硬化率随钼含量增加逐渐增大;在低应变时,主要是压缩变形引起的致密化强化,在高应变时主要是塑性变形引起的加工硬化;随着应变的增加,晶粒由等轴状逐渐变为薄片状,孔隙被压扁、拉长,并分割成更小的微孔,甚至压缩闭合。In order to study the effects of molybdenum content on the microstructure of powder sintered steel and its flow and densification behaviors during compression,the compression experiment of powder sintered steel with dfferent molybdenum content were carried out with universal testing machine.Meanwhile,the microstructure of powder sintered steel with different molybdenum content was observed.In addition,the change law of rheological stress in the compression process was investigated and the deformation characteristics of grains and pores were analyzed.The results show that with the increase of molybdenum content,pearlite and ferrite gradually decrease,while bainite gradually increases.When the molybdenum content reaches 0.85%,the microstructure is mainly composed of fine bainite.The flow and deformation behaviors of the powder sintered steel conform to parabolic strain hardening law.With the increase of molybdenum content,its strength increases and its limit strain decreases.At the same strain,the strain hardening rate increases with the increase of molybdenum content.At low strain,it is mainly the compression deformation that caused densification strengthening,while at high strain,it is mainly the plastic deformation that casued work hardening.With the increase of strain,the grains gradually change from equiaxed to lamellar,and the pores are compressed,elongated,and divided into smaller micropores,even compressed closure.

关 键 词：粉末冶金 钼含量 微观组织 压缩 致密化 

分 类 号：TF124[冶金工程—粉末冶金]