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1、2014年lO月北京航空航天大學學報October2014第40卷第10期JournalofBeijingUniversityofAeronauticsandAstronauticsV01.40No.10纖維增強熔模鑄造復合型殼的性能及斷口形貌呂凱劉向東李艷芬馮華王浩(內蒙古工業(yè)大學材料科學與工程學院,呼和浩特010051)摘要:為提高熔模鑄造硅溶膠型殼的強度性能,采用天然植物/硅酸鋁雙纖維來增強熔模鑄造型殼.將質量比為1:1天然植物/硅酸鋁雙纖維加入到制殼用涂料中來制備型殼試樣,對不同纖維加入量條件下所獲得的纖維增強型殼試樣的常溫強
2、度、不同溫度焙燒后的抗彎強度及高溫自重變形量的變化規(guī)律進行了研究,并利用SEM觀察型殼試樣斷口形貌.結果表明,當纖維加入量從0.2%逐漸增加到1.0%時,其常溫抗彎強度先增加后減小;纖維加入量為0.6%時其常溫抗彎強度值達到2.94MPa.高溫自重變形量則先減小后增大.加入0.6%纖維的增強型殼試樣經(jīng)900℃焙燒后,其抗彎強度達4.04MPa,與未采用纖維增強的型殼試樣的抗彎強度接近.斷口形貌觀察結果表明,纖維增強硅溶膠型殼試樣受力破壞失效主要由于硅溶膠凝膠膜的斷裂、硅酸鋁纖維拔出、斷裂及脫粘等綜合作用所致.關鍵詞:纖維增強型殼;熔模
3、鑄造;強度;斷口形貌;高溫自重變形中圖分類號:TG113文獻標識碼:A文章編號:1001.5965(2014)10—1361-05Propertiesandfracturesurfacemorphologyoffiber-reinforcedshellforinvestmentcastingLiJKaiLiuXiangdongLiYanfenFengHuaWangHao(SchoolofMaterialsScienceandEngineering,InnerMongoliaUniversityofTechnology,Huhhot01
4、0051,China)Abstract:Inordertoimprovethepropertiesofsiliconsolshellforinvestmentcastingprocess,naturalplantfiberscombinedwithaluminumsilicatefibersatnatural.to.a(chǎn)luminumsilicatefibersmassratioof1:1weremixedintotheslurriespreparingforfiber-reinforcedshell.Theflexuralstreng
5、thofspecimensofgreenshells,firedshellsatdifierenttemperaturesandtheself-loadeddeformationofthelatteratelevatedtemDera—turewereinvestigated.ThefractureSRrfaceofshellspecimenswasobservedbySEM.Theresultsshowthatthegreenstrengthofshellspecimensincreasesfirstlyandthendecreas
6、eswithvariationofcontentoffiberfrom0.2%to1.0%.However,theself-loadeddeformationatelevatedtemperaturefirstlydecreasesandthenin.creases.Thegreenstrengthofshellspecimensreinforcedwith0.6%fibersreachesthemaximumof2.94MPa.Thebendingstrengthofshellspecimensreinforcedwith0.6%f
7、ibersfiredat900%reaches4.04MPa,approachingthatofthenon-reinforcedshellspecimens.ItisfoundbySEMthatthefailureofthefiber—reinforcedshellspecimensattheappliedloadisresultedinbreakdownofsiliconsolfilmsandpulling.out,fracturinganddebondingoffibersintheshell.Keywords:fiber-re
8、inforcedshell;investmentcasting;strength;fracturesurfacemorphology;deforma.tionunderweightatelevatedtemperatur