sic泡沫陶瓷%2f铝基复合材料的界面结合及腐蚀行为研究

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1、摘要用主要取决于腐蚀液活化能和腐蚀液温度的变化梯度两个因素，温度上升，腐蚀液活化能被激发，腐蚀液的渗透速率迅速增加，腐蚀速率迅速增加；SiC泡沫陶瓷与Al-xSi（x=20-23）两相界面过渡区域存在一定的位错、间隙、空位等缺陷，并且该处的应力相对较集中，加速了复合材料的腐蚀。关键词：SiC泡沫陶瓷；铝基复合材料；挤压浸渗法；界面结合；力学性能；耐腐蚀性能IIABSTRACTABSTRACTInthispaper,theSiCceramicfoamwaspreparedbyorganicfoamimpregnationandhightemperat

2、uresinteringmethod.Siliconcarbideceramicfoam/aluminummatrixcompositeswasfabricatedbysqueezecastingmethod,SiCceramicfoamandAl-Sialloywereselectedasthereinforcementandthematrixmaterial,respectively.Byusingopticalmicroscope,scanningelectronmicroscope(SEM),X-raydiffraction(XRD),en

3、ergydispersespectroscopy(EDS),brinellhardnesstester,andelectronicuniversaltestingmachine,theinterfacebondingofthecompositeswasstudiedatthefactorofdifferentmatrixmaterialandpouringtemperature.Itsbrinellhardness,bendingstrengthandcorrosionbehaviorweretested.Theresultsareshowedas

4、follows:ThebondingcapacityofAl-SialloyandSiCceramicfoamincreaseswiththeincreasingoftemperature.Undertheconditionofthetemperatureisbelowto780℃,theinterfaceiseasytoseparate.Theappropriatepouringtemperatureis780℃-810℃.Thecompositeswithwellinterfacebondingcanbefabricatedasthehypoe

5、utecticAl-Sialloy(ZL101),eutecticAl-Sialloy(ZL102)andhypereutecticAl-xSi(x=20-23)alloyarechosenforthematrixmaterial.Atransitionzonewithcompactsiliconphaseisformedintheinterface.Themechanismofthecomposites’interfacebondingismixed,itexistsmechanicalinterlockpermeatinglayerandint

6、erfacialreaction.WiththeSiCceramicfoam’saperturediametersincreasing,thehardnessandtheflexurestrengthofcompositesareenhanced.Anditshighflexurestrengthisduetothegoodinterfacebonding.ThefracturemodesinSiliconcarbideceramicfoam/aluminummatrixcompositesaremainlybrittlefractureandcl

7、eavagefracture,buttherearecharacteristicsofductilefractureincomposites.TheAl-xSi(x=20-23)exhibitssuperiorcorrosionresistancewhencompareswiththecomposites.TheSiCceramicfoamhaslargeinfluenceonthecorrosionresistanceofthecomposites.IncreasingthevolumefractionoftheSiCceramicfoamcou

8、ldaggravatethecorrosionprocess.SiCceramicfoamwasnotcorroded.X