摘要
用电镜观察了充氢后双相钢的亚结构,探讨了氢致双相钢机械性能下降的原因。观察表明:充氢后,F相中位错增殖,最后形成胞状亚结构;M相中位错组态变化不明显,但随充氢量增加,裂纹将在M板条界萌生和扩展,有时也横穿M板条;F/M相界充氢后出现宽化现象,并向F相一侧增殖位错,进而界面起裂。M量越多,则此现象越明显。M相与F/M相界起裂对充氢电流密度比充氢时间更为敏感。M相及F/M相界充氢后损伤严重,导致双相钢塑性下降,成为宏观拉伸时易于裂纹萌生和扩展的薄弱部位。
The sub-structures of a hydrogen-charged dual-phase steel were observed by TEM.It was shown that when hydrogen was charged dislocations increased and then the subeells were formed in ferrite.The cracks were initiated and propagated along the lath boundaries and some of cracks crossed the lath in martensite.The interfaces of ferrite-martensite widened and increased disloca- tions in the ferrite phase and then the cracks were initiated.The crack term- inatioa in martensites and interfaces between ferrite and martensite was more sensible to the electrical density than the time of charging hydrogen.The hydrogen damage made the martensite and interface between martensite and ferrite become weak areas in which the cracks were easily initiated in tensile tests.As a result,the mechanical properties of the hydrogen-charged dual- phase steel were decreased.
基金
国家自然科学基金课题
关键词
双相
氢
氢脆
TEM
电镜
钢
组织
hydrogen embrittlement
dual-phase steel
sub-structure
interface
TEM
