等通道角挤压温度对粒状珠光体钢组织和性能的影响  

Effect of equal channel angular pressing temperature on microstructure and properties of granular pearlite steel

作　　者：武永丽 熊毅[1,2] 岳赟 贺甜甜 刘玉亮[1] 任凤章[1,2] WU Yong-li;XIONG Yi;YUE Yun;HE Tian-tian;LIU Yu-liang;REN Feng-zhang(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023,China;Collaborative Innovation Center of New Nonferrous Metal Materials and Advanced Processing Technology Jointly Established by the Ministry of Science and Technology,Luoyang 471023,China)

机构地区：[1]河南科技大学材料科学与工程学院,河南洛阳471023 [2]有色金属新材料与先进加工技术省部共建协同创新中心,河南洛阳471023

出　　处：《材料热处理学报》2021年第1期97-103,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);河南省外国专家与引智项目(HNGD2020009);河南科技大学科技创新团队资助项目(2015XTD006)。

摘　　要：采用Bc方式分别在室温、650℃条件下对高碳粒状珠光体钢进行等通道角挤压(ECAP)变形;借助扫描电镜(SEM)、透射电镜(TEM)、显微硬度计和拉伸试验机研究了不同温度条件下高碳粒状珠光体钢ECAP变形后的微观组织和力学性能。结果表明:冷、温变形4道次后,获得了晶粒尺度分别为400 nm、450 nm的等轴铁素体和颗粒粒径为200 nm、300 nm渗碳体的超微细复相组织;冷变形过程中力学性能随着变形道次的增加而增大,温变形过程中则呈现出先增加后下降的趋势,相同变形道次下冷变形组织的力学性能指标均高于温变形组织;经不同温度ECAP变形后粒状珠光体钢的伸长率均有所下降,但温变形组织的伸长率优于冷变形组织。温变形试样断口形貌与原始粒状珠光体钢相同,均表现为典型的韧性断裂特征,而冷变形试样断口形貌则表现为韧性断裂和少量准解理断裂组成的混合型断裂特征。Equal channel angular pressing(ECAP) deformation of high carbon granular pearlite steel was carried out at room temperature and 650 ℃ respectively by Bc me thod. Microstructure and mechanical properties of the high carbon granular pearlite steel after ECAP deformation at different temperatures were investigated by means of scanning electron microscopy(SEM), transmission electron microscopy(TEM), microhardness tester and tensile tester. The results show that after 4 passes of cold and warm deformation, the ultra-fine micro-duplex structure of equiaxed ferrite with grain size of 400 nm and 450 nm and cementite with particle size of 200 nm and 300 nm are obtained. The mechanical properties of the steel increase with the increase of deformation pass during cold deformation, while the mechanical properties increase at first and then decrease during warm deformation. The mechanical properties of the steel after cold deformation under the same deformation pass are higher than that of after warm deformation. The elongation of the granular pearlite steel decreases after ECAP deformation at different temperatures, but the elongation of the steel after warm deformation is better than that of after cold deformation. The fracture surface morphology of the warm-deformed specimen is the same as that of the original granular pearlite steel, and all exhibit typical ductile fracture characteristics, while the fracture surface morphology of the cold-deformed specimen is characterized by ductile fracture and a small amount of quasi-cleavage fracture.

关 键 词：粒状珠光体钢 等通道角挤压 超微细复相组织 力学性能 断口形貌 

分 类 号：TG142.2[一般工业技术—材料科学与工程]