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ID:32700001
大小:3.63 MB
页数:61页
时间:2019-02-14
《喷射沉积alsi系耐热耐磨合金的组织及性能》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、辽宁工程技术大学硕士学位论文摘要本文以A1一Si系合金为基础,通过添加多种合金元素来提高合金的耐热、耐磨性能。采用喷射沉积快速凝固技术制各了A1—17Si.5Fe一2Ni一3.5Cu一1Mg.2Mn一1V合金。分析了合金的微观组织及形貌,测定了合金的热稳定性、拉伸性能及磨损性能。取得以下主要研究成果:喷射沉积工艺制备的A1.si系合金组织均匀细小,初晶si相的形状基本是颗粒状或块状。热挤压后合金组织十分致密,初晶Si相弥散分布在基体上。T6热处理后的合金部分初晶Si相尖角有所钝化,弥散相的数量增加。挤压态合金在300℃下等温处理不同时间后,初晶Si相没有明显长大:在不同温度等
2、温处理12h时,直至400℃时初晶Si相尺寸才有所增大。挤压后合金室温极限抗拉强度达232.2MPa,T6处理后强度达271.3MPa。合金拉伸时裂纹起源于初晶相本身及初晶相与基体结合处。在磨损100min后,干摩擦条件下的高温磨损失重仅比常温提高了11.87%;只是A390合金失重的60.02%;润滑条件下,100min后高温磨损累积失重量仅为A390合金失重的O.63%,常温磨损未测出失重。关键词:喷射沉积;Al—si合金;显微组织;耐热性;耐磨性;力学性能辽宁工程技术大学硕士学位论文IIABSTRACTMultiplealloyingelementsareselecte
3、dtoimproveheat—andwear—resistanceoftheAl—Sialloy,whichisprepared。byspraydeposition(SD),akindofrapidsolidification(RS)technique.ItschemicalcompositionisA1-17Si一5Fe一2Ni-3.5Cu一1Mg一2Mn—lv.Microstructureandmorphologiesofthealloyareinvestigated.Thermalstability、tensilepropertiesandwear-resistance
4、aremeasured.Themainresultsaresummarizedasfollows:Microstructureofthesprayedalloyiseffectivelyrefined.Themorphologyoftheprimarysiliconphasesismainlygranularorblock—like.Thesiliconphasesaredispersedinthematrixafterbeingextruded。Volumefractionofthedispersedphasesisenlarged。Thereisnoevidentphas
5、ecoarseningofB—Siwhenas—extrudedalloyisheatedat300℃fordifferentdurations;Until400"C,thesizeofprimarySiphasesislargerthanbeforewhenheatedatdifferenttemperaturefor12h.Extrudedalloyhasamaximumtensilestrengthof232.2MPaatroomtemperatureand271.3MPaafterT6treatment.TensilecracksintheSDalloygenerat
6、einsiliconphasesorappearatinterfacesboundarybetweenthesiliconphasesandmatrix.Studyofwearingbehaviorrevealslthatweightlossofthealloyatelevatedtemperatureisincreasedby11.87%thanthatofthealloyatroomtemperaturewithnolubricant,andthevalueis60.02%asmuchasA390alloy’S.ItisthesamecasethatwiththeSDal
7、loyandA390alloyatelevatedtemperaturewithlubricant,thedifferenceofwhichisthatcumulativeweightlossoftheSDalloyis0.63%asmuchasA390alloy’S.WeightlossoftheSDalloyisnearlyzeroatroomtemperature.KeyWords:spraydeposition;Al--Sialloy;microstructure;heat..resistanc
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