性能的影響
王宏明, 劉忠德, 陳 剛
(江蘇大學(xué) 材料科學(xué)與工程學(xué)院, 鎮(zhèn)江 212013)
摘 要: 采用A356-Zr(CO3)2組元通過熔體直接反應(yīng)法原位合成了Al3Zr和Al2O3顆粒增強(qiáng)鋁基復(fù)合材料, 在720 ℃時進(jìn)行常規(guī)金屬模澆注和擠壓鑄造成型。 擠壓鑄造是復(fù)合材料在高壓下的結(jié)晶凝固和塑性變形和強(qiáng)制補縮-密實兩過程的復(fù)合, 增加復(fù)合材料熔點, 改善模壁和熔體熱交換條件, 增加基體形核率。 與金屬模鑄造試樣的組織對比表明： 由于復(fù)合材料的高致密度和細(xì)晶強(qiáng)化, 擠壓鑄造成型復(fù)合材料組織中氣泡和縮孔等澆注缺陷減少了, 而組織致密度提高了, 基體晶粒度減小2~3倍, 復(fù)合材料的抗拉強(qiáng)度和延伸率分別為345 MPa和15.07％, 較金屬模成型復(fù)合材料分別提高1.6和2.15倍, 且擠壓鑄造復(fù)合材料干滑動磨損性能明顯提高。
關(guān)鍵字: 顆粒增強(qiáng)鋁基復(fù)合材料； 擠壓鑄造； 凝固組織；抗拉強(qiáng)度； 干滑動磨損性能
microstructures and properties of (Al3Zr+Al2O3)p/A356 in-situ composites
CAO Jian-feng, WANG Hong-ming, LIU Zhong-de, CHEN Gang
（School of Materials Science and Technology, Jiangsu University,
Zhenjiang 212013, China）
Abstract: The A356-Zr(CO3)2 components were used to synthesize in-situ Al3Zr, Al2O3 particulates reinforced aluminum matrix composites, which were cast by conventional permanent mold and squeeze casting at 720 ℃ respectively. Squeeze casting refers to crystallization, solidification and plastic deforming at high pressure, which combines the compulsory feeding and densification.It enhances the melting point of composites and nucleation rate and improves the heat exchange condition between mold wall and melt.Compared with composites cast by permanent mold, the amount of bubbles and shrinkage holes decreases largely in composites cast by squeeze casting . The tightness of microstructures increases. Meanwhile, the grain size of matrix is decreased by 2-3 times. The tensile strength and elongation are 345 MPa and 15.07％, respectively, which are increased by 1.6 and 2.15 times. The dry sliding property is enhanced largely. The excellent properties are attributed to high tightness and grain strengthening.
Key words: particle reinforced aluminum matrix composites; squeeze casting; microstructure; tensile strength; dry sliding property
