脆性断裂-自学材料.pptVIP

Important terms and concepts: Failure 失效 Fracture 断口 Brittle fracture 脆性断裂 Ductile fracture 塑性断裂 Ductile-to-brittle transition 塑脆转变 Case hardening 表面强化 Fatigue 疲劳 Low-cycle fatigue低周疲劳 High-cycle fatigue高周疲劳 Corrosion fatigue 腐蚀疲劳 Origin 裂纹源 Beachmarks 沙滩印 Fatigue striations 疲劳辉纹 Fibrous texture纤维组织 Mean stress平均应力 Thermal fatigue 热疲劳 Fatigue crack 疲劳裂纹 Fatigue life 疲劳寿命 Fatigue limit 疲劳极限 Endurance limit 容许极限 Fatigue strength 疲劳强度 Creep 蠕变 Neck 颈缩 cup-and-cone 杯突形 Charpy test 夏氏试验 Crack initiation site 裂纹源 Residual compressive stress 残余压缩应力 Constant load 恒载荷 Primary creep/ transient creep 第一蠕变 Secondary creep/Steady-state creep第二蠕变 Tertiary creep 第三蠕变 Plane strain 平面应变 Plane strain fracture toughness 平面应变断裂韧性 Stress intensity factor 应力强度因素 Stress raiser 应力集中源 Fracture mechanics/mode 断裂机制/模式 Transgranular fracture 穿晶断裂 Intergranular fracture 沿晶断裂 Fracture toughness断裂韧性 Impact energy 冲击能 Stress ratio 应力比 Stress amplitude 应力幅 S－N curve S-N曲线 Crack initiation 裂纹萌生 Crack propagation/growth 裂纹扩展 Coalescence n. 合并 small cavities- microvoids 微孔 jeopardy －peril or danger elliptical crack 椭圆形裂纹 Dimples 韧窝 Chevron 人字形 Ridgelike 山脊状 Patterns 花样 Key knowledge points: INTRODUCTION The failure of engineering materials is almost always an undesirable event for several reasons; these human lives that are put in jeopardy (Risk of loss or injury; peril or danger), economic losses, and the interference with the availability of products and services. Even though the causes of failure and the behavior of materials may be known, prevention of failure is difficult to guarantee. The usual causes are improper materials selection and processing and inadequate design of the component or its misuse. It is the responsibility of the engineer to anticipate and plan for possible failure and, in the event that failure does occur, to a