镍基粉末冶金FGH95高温合金的拉伸及低周疲劳性能研究.docx

镍基粉末冶金FGH95高温合金的拉伸及低周疲劳性能研究镍基粉末冶金FGH95高温合金的拉伸及低周疲劳性能研究摘要：在420～650℃的温度范围内,研究了PMFGH95高温合金在应变率0.0001～0.01s-1范围内的拉伸性能及在不同应力比R=-1及R=0下的低周疲劳性能.拉伸试验结果表明:在此温度范围内,应变率对弹性模量、拉伸屈服强度及塑性模量的影响可以忽略不计;并且应变率自0.0001s-1增大至0.01s-1时,弹性模量、拉伸屈服强度及塑性模量受温度的影响也不明显.PMFGH95合金受材料微结构的影响很大,材料含有的微缺陷对其力学性能有非常不利的影响.LCF试验结果表明:PMFGH95合金是循环硬化材料.当应力比R=-1时,温度对LCF寿命的影响很小;但在应力比R=0时,LCF寿命受温度的.影响很大,且随着温度的增加材料的低周疲劳寿命减小.SEM断口扫描发现,断裂表面有很多的解理面,但没有疲劳条带,且此断裂模式下没有明显的塑性变形,所以FGH95合金的低周疲劳寿命几乎是由裂纹萌生阶段决定的.Abstract：Thetensilebehaviorofanickel-basepowdermetallurgy(PM)FGH95superalloywasstudiedinthetemperaturerangefrom420℃to650℃withstrainratefrom0.0001s-1to0.01s-1.Thelowcyclefatigue(LCF)behaviorofthissuperalloywasinvestigatedinthetemperaturerangefrom420℃to650℃underpush-pullmode(R=-1)andpullmode(R=0)atstrainrateof0.001S-1.TheresultsoftensiletestingshowthattheeffectofstrainrateontheYoungsmodulus,tensileyieldstrength,andplasticmoduluscanbeneglectedintheexperimentaltemperaturerange.AndtheinfluenceoftemperatureontheYoungsmodulus,tensileyieldstrength,andplasticmodulusisnotobviousinthestrainraterangefrom0.0001s-1toO.01s-1.ThePMFGH95issensitivetothemicro-defect.whichhasasignificantdeleteriouseffectonFGH95materialmechanicalbehavior.TheresultsofLCFrevealthatthePMFGH95isthecyclichardeningmaterial.FormodeR=-1.theeffectoftemperatureonLCFlifecanbeneglected;butformodeR=0,thetemperaturehasprofoundinfluenceontheLCFlife.Atthiscase,theLCFlifedecreasesdrasticallywiththetemperatureincreasing.TheSEMinvestigationofLCFspecimensshowsthattherearealotofcleavagesonfracturesurface,fatiguestriationsareabsent,andthisfracturemodemaynotinvolvesignificantplasticdeformation.SotheLCFlifeofPMFGH95isalmostdeterminedbythecrackinitiationstage.作者：崔伟华万建松岳珠峰杨治国Author：CuiWeihua  WanJiansong  YueZhufeng  YangZhiguo作者单位：西北工业大学,陕西西安,710072期刊：稀有金属材料与工程 ISTICEISCIPKUJournal：RAREMETALMATERIALSANDENGINEERING年，卷(期)：2007, 36(12)分类号：V256V250.3关键词：镍基粉末冶金FGH95合金  拉伸性能  低周疲劳  应变率影响  温度效应  断裂模