双相不锈钢中奥氏体相内裂纹扩展路径的透射电镜原位观察

IN SITU OBSERVATION ON CRACK PROPAGATING PATH IN AUSTENITE OF A DUPLEX STAINLESS STEEL

在透射电镜下原位观察了裂纹在双相不锈钢中的扩展过程。结果表明,裂纹在双相不锈钢中奥氏体晶粒内扩展时常呈较大的Z字形扩展路径。并且,在主裂纹前端奥氏体晶粒内形核的小裂纹与主裂纹有较强的交互作用,小裂纹尖端二次滑移系的选择和扩展路径为小裂纹尖端应力场和主裂纹尖端应力场共同支配。

The crack propagation in austenite phase of the ferrite-austenite duplex stainless steel, observed in situ under TEM, was found as zigzag path frequently. The main crack and the microcrack, nucleated in the austenite grain ahead of the main crack, caused an interaction. The choice of the secondary slip system at micro- crack tip and the propagating path of microcrack are controlled by the microcrack tip stress field and the stress field of the main crack.