粉末冶金高铝锌基合金及颗粒增强材料的制备与性能

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1、江苏大学高教硕士学位论文摘要本研究采用传统粉末冶金工艺，即以纯金属粉末及普通工业磨料n—SiC．为原料，在空气气氛中液相烧结的方法制各了高铝锌基合金和体积分数为5％的SiC颗粒增强锌铝摹复合材科，开拓了一种锌铝基复合材料制各的新方法(有关采用传统粉末冶金法制取SiG增强锌铝基复合材料的报道还未见到)。同时对烧结体的性能进行测试，结果表明：烧结体发生体积膨胀，相对致密度减小，粉末冶金高铝锌基合金的抗压强度和硬度比相同成分的铸造锌铝合金有所降低。实验获得的最佳烧结工艺为温度425～430℃，时问4～5小时。用该工艺制备的粉末冶金高铝锌基合金具有良好的耐磨性。用SiC颗粒增强的复合材料的硬度和

2、抗压强度均比相同工艺下劁备的基体会金大大提高，耐磨性显著提高，磨损量远小于基体合金和铸造合金。主要原因是复合材料形成了共析组织，相界面增多，塑性变形抗力增大，且硬质点数量增加。利用sEM、XRD对显微组织和物相进行分析，结果表明：粉末冶金锌铝合金是由富铝相(或纯铝相)和富锌相组成，还出现片层状两相相间的共析组织，而复合材料的基体几乎全为共析组织，这与铸造Z^27合金的显微组织有明显的区别，原子沿晶界(相界)和自由表面的扩散在共析组织的形成过程中起到了关键性的作用。关键词：粉末冶金；高铝锌基合金：液相烧结；SiC颗粒增强江苏大学高教硕士学位论文ABSTRA(、TBythetradition

3、alpowdermetallurgytechnique，thepowdermetallurgyofhighaluminumZn-basedalloysandZn-AImatrixCompositereinforcedby5v01％SiCparticlesWereproducedwithpuremetalpowderand口·SiCparticlesbyrecallsofliquidphasesinteringatatmosphere．AnewprocesswasdevelopedinpreparingZn-AImatrixComposite(Thereportaboutpreparing

4、Zn-AImatrixcompositereinforcedbySiCparticlesbasedonthetraditionalpowdermetallurgytechniquehasnotbeenfoundyet．)．Thepropertiesofthesinterexlbodywereexamined．Theresultsoftheexperimentshowedthatthesinteredbodyexpandedandtherelativedensitydecreased．ThecompressivestrengthandhardnessDftheP／MZn-AIalloysd

5、ecreasedasComparedwiththecastingalloyofthesanleComposition．TheexperimentshowedthattheoptimumprocessWaSsintedngat425-430"Cfor4-5hours．Thealloymadebythisprocesspossessedbetterwear-resistance．Theexperimentalresultsindicatedthatthe西mpressivestrengthandhardnessofthesinteredalloyreinforcedbytheSiCparti

6、cleswereobviouslyhigherthanthatofthematrixalloyproducedwiththesameprocess．Theweal"resistanceofthecompositewasremarkablyimprovedandthewearmagnitudewasmuchlessthanthatofthematrixalloyandcastingalloy．Themainreasonshouldbetheformingoftheeuteetoidstructure，theincreasingofthephaseinterfaces，theenhancin

7、goftheplasticdeformationresistance．aswellastheincreasingofthehardparticles．ThemicrostuctureandthephasewereanalyzedwithSEMandXRD．TheexperimentalresultsindicatedthattheP／MZn-AIalloysconsistedofaluminum—enriched(orpurealu