(東南大學(xué) 材料科學(xué)與工程系，南京210096)
摘 要: 用攪拌法制備了以MB2為基、以SiC顆粒為增強(qiáng)體的鎂基復(fù)合材料，鑄錠在390 ℃熱擠壓成棒材。 在溫度為380～560 ℃和應(yīng)變速率為2.08×10-3s-1～5.21×10-1s-1的范圍內(nèi)，測(cè)試了擠壓態(tài)MB2/10%SiC(體積分?jǐn)?shù))和MB2/5%SiC鎂基復(fù)合材料的超塑性。M B2/10%SiC在溫度為525℃、應(yīng)變速率為2.08×10-1s-1時(shí)最大延伸率可達(dá)228%，應(yīng)變速率敏感性指數(shù)為0.39。超塑性拉伸斷口上存在絲棒狀物質(zhì)。
關(guān)鍵字: 鎂/碳化硅復(fù)合材料；高應(yīng)變速率；超塑性
（Department of Materials Science and Engineering, Southeast University, Nanjing 210096, P.R.China）
Abstract:Ingots of MB2 (magnesium-based alloy) matrix composites reinforced with SiC particulates (2 μm), of 10 % or 5%(in volume fraction) were prepared by stir casting and then extruded with a reduction ratio of 49∶1 at 390℃. Superplasticity of the composites was investigated at 380 ℃～560 ℃ and with strain rate from 2.08×10-3s-1 to 5.21×10-1s-1. The maximum of total elongation as high as 228% was obtained in MB2/10%SiC composite at 525℃ with a strain rate of 2.08×10-1s-1, and the strain rate sensitivity exponent (m) was 0.39. Filament was observed on the fracture surface of the specimens showing superplasticity.
Key words: Mg/SiC composite; high strain rate; superplasticity
