无机非金属材料工程专业英语 第8章.ppt

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1、Chapter8FailureWhatistherealnatureforthedifferentappearanceoffracturesection?Whystudyfailure?Airplaneorcarcrash,bridgebreaking,machinebreakingdownareall,tosomesense,relatedtothefailureofengineeringmaterials.Thebestwaytopreventsuchin-servicefailuresist

2、ostudythemechanicsofthevariousfailuremodesanddesignthestructuresorcomponentsappropriately.Whatshouldyoubeabletodoafterstudyingthischapter?Havethebasicknowledgeofthemajortypesofengineeringmaterialsfailure.Understandthemechanicsofvariousfracturemodes.Im

3、portanttermsandconcepts:Failure失效Fracture断口Brittlefracture脆性断裂Ductilefracture塑性断裂Ductile-to-brittletransition塑脆转变Casehardening表面强化Fatigue疲劳Low-cyclefatigue低周疲劳High-cyclefatigue高周疲劳Corrosionfatigue腐蚀疲劳Origin裂纹源Beachmarks沙滩印Fatiguestriations疲劳辉纹Fibroust

4、exture纤维组织Meanstress平均应力Thermalfatigue热疲劳Fatiguecrack疲劳裂纹Fatiguelife疲劳寿命Fatiguelimit疲劳极限Endurancelimit容许极限Fatiguestrength疲劳强度Creep蠕变Neck颈缩cup-and-cone杯突形Charpytest夏氏试验Crackinitiationsite裂纹源Residualcompressivestress残余压缩应力Constantload恒载荷Primarycreep/tra

5、nsientcreep第一级蠕变Secondarycreep/Steady-statecreep第二级蠕变Tertiarycreep第三级蠕变Planestrain平面应变Planestrainfracturetoughness平面应变断裂韧性Stressintensityfactor应力强度因素Stressraiser应力集中源Fracturemechanics/mode断裂机制/模式Transgranularfracture穿晶断裂Intergranularfracture沿晶断裂Fractu

6、retoughness断裂韧性Impactenergy冲击能Stressratio应力比Stressamplitude应力幅S－NcurveS-N曲线Crackinitiation裂纹萌生Crackpropagation/growth裂纹扩展Coalescencen.合并smallcavities-microvoids微孔jeopardy－perilordangerellipticalcrack椭圆形裂纹Dimples韧窝Chevron人字形Ridgelike山脊状Patterns花样Keykno

7、wledgepoints:INTRODUCTIONThefailureofengineeringmaterialsisalmostalwaysanundesirableeventforseveralreasons;thesehumanlivesthatareputinjeopardy(Riskoflossorinjury;perilordanger),economiclosses,andtheinterferencewiththeavailabilityofproductsandservices.

8、Eventhoughthecausesoffailureandthebehaviorofmaterialsmaybeknown,preventionoffailureisdifficulttoguarantee.Theusualcausesareimpropermaterialsselectionandprocessingandinadequatedesignofthecomponentoritsmisuse.Itistheresponsibilityoftheengineerto