(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: 采用熱模金屬型工藝， 離心鑄造自生增強的Zn-27Al-6.3Mg-3.7Si合金復(fù)合材料。 研究結(jié)果表明： 該合金內(nèi)層聚集大量塊狀初生Mg↓2Si、 少量塊狀初生Si， 中層不含初生Mg2Si和初生Si， 外層含少量初生Mg2Si和初生Si； Zn-27Al-6.3Mg-3.7Si合金在凝固過程中， 先后經(jīng)歷了初生Si和初生Mg↓2Si的析出、 富Al的固溶Zn相析出、 Mg-Zn化合物的析出， 以及發(fā)生三元或四元共晶反應(yīng)； 初生Mg2Si和初生Si的位置、 數(shù)量和分布決定于其內(nèi)浮速度和離心力場作用下的凝固速度；含有初生Mg2Si和初生Si的內(nèi)層和外層比中層具有更高的硬度和耐磨性。
關(guān)鍵字: 離心鑄造； Zn-27Al-Mg-Si 合金； 自生復(fù)合材料； Mg2Si； Si
ZHAI Chun-quan, MA Chun-jiang, DING Wen-jiang
（State Key Laboratory of Metal Matrix Composites,
Shanghai Jiaotong University, Shanghai 200030, China）
Abstract:In-situ composite of Zn-27Al-6.3Mg-3.7Si alloy was fabricated by centrifugal casting using the heated permanent mold. This kind of composite is consisted of three layers, inner layer segregates lots of blocky primary Mg2Si and a little blocky primary Si, middle layer contains no primary Mg2Si and primary Si, outer layer contains a little. Zn-27Al-6.3Mg-3.7Si alloy solidifies according to following steps: firstly, the precipitation of primary Si and primary Mg2Si, secondly, the precipitation of Zn-phase enriched by Al, thirdly, the precipitation of Mg-Zn compound, and lastly, the occurrence of ternary or quaternary eutectic reaction. The position, quantity and distribution of primary Mg2Si and primary Si are determined by solidification velocity under the effect of centrifugal force and their floating velocity inward. The inner and outer layer contained primary Mg2Si and primary Si exhibit much higher hardness and wear resistance than the middle layer.
Key words: centrifugal casting; Zn-27Al-Mg-Si alloy; in-situ composites; Mg2Si; Si
