热冲压钢B1500HS在不同应变速率下的氢脆现象研究  

Hydrogen embrittlement phenomenon of hot stamped steel B1500HS at different strain rates

作　　者：张惠臻 张晓欣 陈扬[1,2] 韩先洪 ZHANG Hui-zhen;ZHANG Xiao-xin;CHEN Yang;HAN Xian-hong(National Engineering Research Center of Die&Mold CAD,Shanghai Jiao Tong University,Shanghai 200030,China;School of Material Science and Engineering,Shanghai Jiao Tong University,Shanghai 200030,China)

机构地区：[1]上海交通大学模具CAD国家工程研究中心,上海200030 [2]上海交通大学材料科学与工程学院,上海200030

出　　处：《塑性工程学报》2020年第5期66-73,共8页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51775336);上海市科委资助项目(19XD1401900)。

摘　　要：通过电化学充氢和不同应变速率拉伸试验,研究应变速率对热冲压钢B1500HS氢脆敏感性的影响。通过微观断口形貌观测,分析不同应变速率下充氢热冲压钢断裂形式的差异,并进一步对其机理进行探究。结果表明,随着应变速率的降低,热冲压钢的强度和塑性损失量逐渐增加,说明慢应变速率下氢脆现象更加明显;慢应变速率下热冲压钢拉伸断口呈准解理状,而快应变速率下则呈现小韧窝状,其断裂形式呈现出由脆性断裂向韧性断裂的转变。分析其原因主要是在慢应变速率下,氢有足够的时间扩散至孔洞、夹杂等缺陷位置,从而促进裂纹的产生和扩展,导致其具有更高的氢脆敏感性。The effects of strain rate on the hydrogen embrittlement sensitivity of hot stamped steel B1500 HS were investigated through electrochemical hydrogen charging and tensile tests with different strain rates. The difference of fracture modes of hydrogen charged hot stamped steel was analyzed through microscopic fracture morphology observations,furthermore,the mechanism was studied. The results show that the strength and plasticity loss of hot stamped steel gradually increase with the decrease of strain rate,which indicates that the hydrogen embrittlement phenomenon is more obvious at slow strain rate;the tensile fracture of hot stamped steel is quasi-cleavage at slow strain rate,while it shows a small dimple-like shape at high strain rate,which exhibits a transition from brittle fracture to ductile fracture.The main reason is that the hydrogen embrittlement sensitivity increases at slow strain rate,since hydrogen has more time to diffuse to the defect regions such as voids and inclusions to promote crack generation and expansion.

关 键 词：热冲压钢 氢脆 应变速率 断裂形式 

分 类 号：TG386.2[金属学及工艺—金属压力加工]