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1、碩上論文無壓浸滲法制備SiCp/AI復(fù)合材料的研究摘要高體積分?jǐn)?shù)SiCp/A1復(fù)合材料具有比強(qiáng)度高、耐磨性好和尺寸穩(wěn)定性好等優(yōu)點(diǎn),被廣泛應(yīng)用于航空航天、軍事武器、汽車以及電子封裝等方面。無壓浸滲法在制備高體積分?jǐn)?shù)SiCp/A1有著顯著的低成本優(yōu)勢(shì)和最強(qiáng)的近凈形制備能力,但是SiC和A1之間的化學(xué)相容性差導(dǎo)致SiC/A1系統(tǒng)的潤(rùn)濕性較差,而且在無壓浸滲溫度下由于SiC的分解易生成有害界面反應(yīng)產(chǎn)物A14C3。本課題主要研究了SiC的表面改性、鋁合金成分和各工藝參數(shù)對(duì)無壓浸滲工藝和復(fù)合材料性能的影響,以得出較佳的制備工藝過程。為改善SiC的潤(rùn)濕性,對(duì)SiC顆粒分別進(jìn)行高溫氧化和表面化學(xué)
2、鍍鎳處理,研究表明這兩種方法均能顯著改善SiC/Al的潤(rùn)濕性,促使界面形成新相加強(qiáng)界面結(jié)合,有效保護(hù)SiC不被Al液侵蝕。A1基中添加的Mg元素在浸滲過程中起促進(jìn)劑的作用,擴(kuò)散并富集于SiC/A1界面上的Mg與鋁液表面的氧化膜發(fā)生反應(yīng),降低界面張力,提高SiC/A1的濕潤(rùn)性。趾基中添加一定含量的Si元素可以抑制不利的界面反應(yīng)。N2作為浸滲保護(hù)氣氛,不但可防止原材料氧化,而且可以固定合金元素Mg。1100℃的浸滲高溫促進(jìn)鋁表面的A1203膜破壞,以改善鋁與SiC顆粒的潤(rùn)濕性。2h的浸滲保溫時(shí)間使SiCp/A1復(fù)合材料充分致密化,致密度可達(dá)97%以上。復(fù)合材料的硬度和抗彎強(qiáng)度均隨著S
3、iC顆粒尺寸的減小和致密度的提高而增大,其中以240目SiC制備的復(fù)合材料綜合力學(xué)性能較佳。SiC/A1的界面結(jié)合緊密有利于提高復(fù)合材料的力學(xué)性能。關(guān)鍵詞:SiCp/A1復(fù)合材料;無壓浸滲;SiC預(yù)氧化;鍍鎳;合金元素;界面碩士論文AbstractHigh-volumeSiC舢compositematerialshavemanyexcellentpropertiessuchashighstrength,wellwearresistanceandgooddimensionalstability,SOtheycouldbeusedinaerospace,militaryweapons
4、,carsandelectronicpackaging,etc.ThepressurelessinfiltrationofSiCporousperformsbyliquidaluminumisasimpleandeconomicroutefortheproductionofhigh—volumeSiCp/A1composites.WeCanobtainnear-ornet-shapecompositeswithuniforilldistributionofthereinforcementsandhighdimensionalstabilitybythisway.However,w
5、ithlowchemicalcompatibility,SiC/A1systemhaspoorwettability.Inaddition,atthepressurelessinfiltrationtemperature;thereexiststhepotentialforthedevelopmentoftheharmfulreactionwhichproductA14C3ontheA1/SiCinterface.TmspaperinvestigatedtheeffectofthesurfacemodificationoftheSiCp,thecomponentsofalumin
6、umalloyandalltechnicalparameterstopressurelessinfiltrationtechniquesandpropertiesofcompositematerialstogetbeRerpreparationprocess.InordertoimprovethewettabilityofSiC,wecouldformacoatingofSi02bythepassiveoxidationoftheSiCandchemicalplatingofNirespectively.Researchesshowedthatthesetwomethodscan
7、significantlyimprovethewettabilityofSiC/A1system,andtheformationofnewphasesinducedastrongbondingbetweenthematrixandthereinforcementwhichpreventedthepotentialproductionofAhC3.ThepresenceofMginA1matrixcouldpromotepressurelessinfiltration.Themai