(上海交通大學(xué)金屬基復(fù)合材料國家重點(diǎn)實(shí)驗(yàn)室， 上海 200030)
摘 要: 用擠壓鑄造、擠壓比僅為10∶1的擠壓以及進(jìn)一步的軋制成功地制備了具有高應(yīng)變速率超塑性行為的β-SiC晶須增強(qiáng)LY12復(fù)合材料。該復(fù)合材料晶粒細(xì)小，約為2μm；在溫度為803K和初始應(yīng)變速率為1.1×10-1s-1時(shí)，延伸率達(dá)350％，應(yīng)變速率敏感系數(shù) m 值約為0.35；超塑性變形的主要機(jī)制是細(xì)小晶粒的晶界滑動(dòng)，適當(dāng)?shù)奈⒘恳合嘤欣谠搹?fù)合材料的高應(yīng)變速率超塑性。
關(guān)鍵字: 高應(yīng)變速率超塑性 鋁基復(fù)合材料 擠壓鑄造
（State Key Laboratory of Metal Matrix Composites, Shanghai JiaoTong University,Shanghai 200030, P. R. China）
Abstract:A β-SiC whisker reinforced LY12 aluminum composite expected to exhibit high strain rate superplasticity has been successfully fabricated by squeeze casting and rolling after extrusion with a low extrusion ratio of 10∶1. The as-processed composite has a fine grain size of about 2μm, and exhibits a maximum total elongation of 350% and a strain rate sensitivity of about 0.35 at the initial strain rate of 1.1×10-1s-1 at 803 K. The dominant process of superplastic deformation is fine grain boundary sliding, and an appropriately small amount of liquid phase can enhance the high strain rate superplasticity of the composite.
Key words: high strain rate superplasticity aluminum matrix composites squeeze casting
