摘要
采用等径角挤压的方法制备了微复相组织(α+θ)的超细晶粒高碳钢,借助分离式霍普金森压杆研究了超细晶粒高碳钢不同应变速率条件下的动态力学行为,并采用扫描电镜、透射电镜观察其微观组织演变过程。结果表明:原始组织为层片状珠光体的T8钢经四道次等径角挤压变形后可制备出晶粒尺度在亚微米量级的微复相组织(α+θ)的超细晶粒高碳钢。在动态压缩变形过程中,超细晶粒高碳钢发生了绝热剪切现象,随着应变速率的增大变形抗力呈增加趋势,绝热剪切带内的显微硬度先下降后升高,但明显高于基体组织硬度。绝热剪切带内的铁素体基体发生了动态再结晶,同时弥散析出大量细小的渗碳体颗粒,形成晶粒尺寸更加细小的超细微复相组织(α+θ)。
Ultra-fine-grained high carbon steel with micro-duplex microstructure(α+θ)was prepared by means of equal channel angular pressing(ECAP).The dynamic mechanical behavior of the ultra-fine-grained high carbon steel under different strain rates was studied by separate Hopkinson pressure bar system,and the microstructure evolution process was observed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results show that the ultra-fine-grained high carbon steel with micro-duplex microstructure(α+θ)at sub-micron scale can be prepared by equal channel angular pressing with four passes using T8 steel with lamellar pearlite as raw material.In the process of dynamic compression deformation,the adiabatic shear phenomenon occurs in the ultra-finegrained high carbon steel.With the increase of strain rate,the deformation resistance increases,and the microhardness in the adiabatic shear band decreases first and then increases,but obviously higher than that of the matrix microstructure.The ferrite matrix in the adiabatic shear band undergoes dynamic recrystallization and disperses and precipitates a large number of fine cementite particles to form the ultra-fine micro-duplex microstructure(α+θ)with finer grain size.
作者
周甜
熊毅
马云飞
武永丽
任凤章
ZHOU Tian;XIONG Yi;MA Yun-fei;WU Yong-li;REN Feng-zhang(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023,China;Collaborative Innovation Center of Nonferrous Metals,Henan University of Science and Technology,Luoyang 471023,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2020年第5期126-132,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(U1804146,51801054)
河南省高校科技创新人才支持计划项目(17HASTIT026)
河南省教育厅科技计划项目(16A430005)
河南科技大学科技创新团队资助项目(2015XTD006)。
关键词
超细晶粒高碳钢
动态压缩变形
应力应变曲线
微观组织
绝热剪切带
ultra-fine-grained high carbon steel
dynamic compression deformation
stress-strain curve
microstructure
adiabatic shear band
