(东南大学 材料科学与工程系,南京210096)
摘 要: 用搅拌法制备了以MB2为基、以SiC颗粒为增强体的镁基复合材料,铸锭在390 ℃热挤压成棒材。 在温度为380~560 ℃和应变速率为2.08×10-3s-1~5.21×10-1s-1的范围内,测试了挤压态MB2/10%SiC(体积分数)和MB2/5%SiC镁基复合材料的超塑性。M B2/10%SiC在温度为525℃、应变速率为2.08×10-1s-1时最大延伸率可达228%,应变速率敏感性指数为0.39。超塑性拉伸断口上存在丝棒状物质。
关键字: 镁/碳化硅复合材料;高应变速率;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