22MnB5高强钢板热塑性及断裂行为  

Thermoplasticity and fracture behavior of 22MnB5 high strength steel plate

作　　者：李敏 杜帅 李颖 何文武[1] LI Min;DU Shuai;LI Ying;HE Wen-wu(School of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学材料科学与工程学院,山西太原030024

出　　处：《塑性工程学报》2022年第10期202-207,共6页Journal of Plasticity Engineering

基　　金：山西省重点学科建设经费资助项目(2019KJ029)。

摘　　要：采用Gleeble-1500D热模拟试验机在变形温度为600~900℃,应变速率为0.1~10 s^(-1)条件下对22MnB5高强钢板进行了热拉伸试验,并通过扫描电镜和超景深光学显微镜观察了其断口形貌及金相组织。结果表明,22MnB5钢的应力-应变曲线表现为动态回复型,变形温度越小、应变速率越大时,22MnB5钢的流变应力越大;断裂机制为微孔聚集型韧性断裂;当变形温度小于900℃、应变速率小于10 s^(-1)时,颈缩、断裂应变和断口韧窝直径随温度和应变速率的增大而增大。试样金相组织在变形温度为800℃、应变速率为1 s^(-1)时再结晶程度比较充分,晶粒明显细化;韧窝越大,再结晶程度越充分,晶粒尺寸越细,临界断裂应变越大,材料热塑性变形能力越强;采用引入Zener-Hollomon参数改进后的Cockroft-Latham准则能较为成功地预测22MnB5高强钢的断裂行为。The hot tensile tests of 22MnB5 high strength steel plate under the conditions of deformation temperature of 600-900℃and strain rate of 0.1-10 s^(-1) were carried out by Gleeble-1500D thermal simulator,and the fracture morphology and metallorgraphic structure were observed by scanning electron microscope and ultra-depth optical microscope.The results show that the stress-strain curves of 22MnB5 steel show dynamic recovery.The smaller the deformation temperature is and the greater the strain rate is,the greater the flow stress of 22MnB5 steel is.The fracture mechanism is microporous aggregation ductile fracture.When the deformation temperature is less than 900℃and the strain rate is less than 10 s^(-1),the necking,fracture strain and diameter of fracture dimples increase with the increase of temperature and strain rate.When the deformation temperature is 800℃and the strain rate is 1 s^(-1),the recrystallization degree of the samples is sufficient,and the grain is obviously refined.The larger the dimple is,the more sufficient the recrystallization degree is,the finer the grain size is,the larger the fracture strain is,and the stronger the thermoplastic deformation ability of the material is.The improved Cockroft-Latham criterion with Zener-Hollomon parameter can be used to predict the fracture behavior of 22MnB5 high strength steel successfully.

关 键 词：22MnB5高强钢 断口形貌 热塑性 改进的Cockroft-Latham断裂准则 

分 类 号：TG142.14[一般工业技术—材料科学与工程]