(上海交通大學(xué) 金屬基復(fù)合材料國家重點實驗室， 上海 200030)
摘 要: 采用熱模金屬型離心鑄造Zn-27Al-5Si合金，獲得了內(nèi)層含大量初晶Si，外層有少量初晶Si，中層為細(xì)小共晶Si的表面復(fù)合材料。考察了復(fù)合材料的組織形貌和復(fù)合材料的形成過程，以及模溫和轉(zhuǎn)速對組織的影響。結(jié)果表明，隨著模溫的提高，初晶Si、共晶Si和基體組織變得粗大；隨管模轉(zhuǎn)速的增加， 初晶Si在內(nèi)側(cè)富集層厚度減小，初晶Si面積比增大。復(fù)合材料的內(nèi)層由于聚集了大量初晶Si而具有較高的硬度和較優(yōu)的耐磨性。復(fù)合材料的斷裂方式為脆性斷裂，含共晶Si的中層在斷裂中比含塊狀初晶Si的內(nèi)層經(jīng)歷了更多的塑性變形。
關(guān)鍵字: 離心鑄造； Zn-Al-Si合金； 自生表面復(fù)合材料；耐磨性； 斷裂
MA Chun-jiang，ZHU Yan-ping, HE Wei, DING Wen-jiang
（State Key Lab of Metal Matrix Composites,
Shanghai Jiaotong University, Shanghai 200030, P.R.China）
Abstract:A new in-situ Zn-Al-Si surface composites was fabricated by using centrifugal casting. A high-volume fraction of primary Si particles in the inner layer was achieved. The formation mechanism of the gradient was discussed. The effect of technological parameters on the composites was investigated. Testing results show that the hardness and wear resistance of the composites depend mainly on the distribution of the primary silicon particles along radial direction. The inner layer of the composite shows the highest hardness and best wear properties. The fracture mode of the composites is primarily brittle. The inner layer of the composite exhibits more deformation than the inner layer during the fracture.
Key words: centrifugal casting; Zn-Al-Si alloy; in-situ surface composites; wear; fracture
