·1064 北京科技大学学报 第36卷 应方集中 分wnm 2 图6C32N7M3N钢在人工海水中空蚀39h后扫描电镜形貌.(a)表面粗糙形貌及空蚀洞：(b)解理状小平面：（©）失稳裂纹扩展及应 力集中裂纹：()韧性撕裂及空蚀微孔 Fig.6 SEM micrographs of Cr32Ni7Mo3N steel after cavitation in artificial seawater for 39 h:(a)surface roughness and cavities:(b)cleavage-ike facets:(c)unstable crack growth and stress concentration crack:(d)ductile tearing features and microvoids a b 裂 图7C32N7M3N钢在蒸馏水和人工海水中空蚀84h后扫描电镜形貌.(a)蒸馏水中空蚀奥氏体和铁素体的破坏：(b)蒸馏水空蚀疲劳 辉纹及微裂纹形貌：()人工海水空蚀蜂窝状空蚀坑形貌：()人工海水空蚀微裂纹形貌 Fig.7 SEM micrographs of Cr32Ni7Mo3N steel after cavitation in distilled water and artificial seawater for 84 h:(a)damage to ferrite and austenite in distilled water:(b)fatigue striations in distilled water:(c)damage to ferrite and austenite in artificial seawater;(d)severe ductile tearing and microcracks in artificial seawater北 京 科 技 大 学 学 报 第 36 卷 图 6 Cr32Ni7Mo3N 钢在人工海水中空蚀 39 h 后扫描电镜形貌． ( a) 表面粗糙形貌及空蚀洞; ( b) 解理状小平面; ( c) 失稳裂纹扩展及应 力集中裂纹; ( d) 韧性撕裂及空蚀微孔 Fig． 6 SEM micrographs of Cr32Ni7Mo3N steel after cavitation in artificial seawater for 39 h: ( a) surface roughness and cavities; ( b) cleavage-like facets; ( c) unstable crack growth and stress concentration crack; ( d) ductile tearing features and microvoids 图 7 Cr32Ni7Mo3N 钢在蒸馏水和人工海水中空蚀 84 h 后扫描电镜形貌． ( a) 蒸馏水中空蚀奥氏体和铁素体的破坏; ( b) 蒸馏水空蚀疲劳 辉纹及微裂纹形貌; ( c) 人工海水空蚀蜂窝状空蚀坑形貌; ( d) 人工海水空蚀微裂纹形貌 Fig． 7 SEM micrographs of Cr32Ni7Mo3N steel after cavitation in distilled water and artificial seawater for 84 h: ( a) damage to ferrite and austenite in distilled water; ( b) fatigue striations in distilled water; ( c) damage to ferrite and austenite in artificial seawater; ( d) severe ductile tearing and microcracks in artificial seawater · 4601 ·