【摘要】 研究了20Cr11MoVNbNB马氏体热强钢在550—65℃范围内蠕变孔洞的形成及蠕变裂纹的发展发现蠕变孔洞主要在原奥氏体晶界和原板条马氏体边界上的淬火未溶大颗粒Nb（C，N）及M23C6碳化物处形成，孔洞在原奥氏体晶界形成倾向不占优势：蠕变裂纹沿垂直应力方向横穿原奥氏体晶界及原板条马氏体边界向晶内扩展，最终导致穿晶断裂.更多还原

【Abstract】 Studies were made on the nucleation of creep cavities and propagation of creep cracks in steel 20Cr11MoVNbNB at 550-650℃. Results show that creep cavities are mainly nucleated at the big particles of undissolved Nb (C, N) and M23C6 carbides, both of which exist at prior austenite grain boundaries and lath martensite boundaries. It is also found that creep creacks crossed the prior austenite grain boundaries and lath martensite boundaries along the direction normal to applied stress, propagated into the grains, and finally leaded to the transgranular fracture.更多还原