Tempering mechanism of lath martensite induced in IF steel under high pressure  

作　　者：Zuohua Wang Haidong Sun Xiaogang Guo Peng Wang Ning Liu Dongli Yu Hongwang Zhang 

机构地区：[1]National Engineering Research Center for Equipment and Technology of Cold Strip Rolling,College of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China [2]State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,China [3]Liren College of Yanshan University,Yanshan University,Qinhuangdao 066004,China

出　　处：《Journal of Materials Science & Technology》2023年第29期148-160,共13页材料科学技术（英文版）

基　　金：the Natural Science Foundation-Steel and Iron Foundation of Hebei Province(No.E2021203051);the Hundred Outstanding Creative Talents Projects in Universities of Hebei Province,China,and the Project Program of Heavy Machinery Collaborative Innovation Center,China.

摘　　要：In this paper,low-and high-strength lath martensite(350 and 640 HV)was fabricated in an IF steel via high pressure martensitic transformation.The microstructure and the softening during their tempering from 200°C to 800°C for 1 h were systematically investigated.A carbon-irrelevant tempering process was proposed,exhibiting a three-stage structural evolution pattern depending upon the tempering de-gree(1-(HV-HV FP)/(HV NP-HV FP),where the HV is the instant hardness,HV NP is the non-tempered hard-ness and HV FP is the fully tempered hardness):(1)low tempered(<10%),removing the loose dislocations and dislocation boundaries within martensitic variants;(2)medium tempered(10%-50%),eliminating the martensitic variant laths via the migration of their terminal tips;(3)highly tempered(>50%),clearing up the remained variant laths via the migration of the triple junctions.Martensite-type microstructure is tailored by low-index lamellar variant boundaries and is thus intrinsically thermally stable,whereas the mobile terminal tips decrease the tempering resistance.The underlying mechanism for such carbon-irrelevant process was discussed and the potential effect on the tempering behavior of carbon-contained martensite was highlighted.

关 键 词：Tempering mechanism Lath martensite IF steel Terminal tip migration High pressure 

分 类 号：TG142.71[一般工业技术—材料科学与工程]