冷热循环对颗粒增强铝基复合材料微屈服行为的影响

来源期刊：中国有色金属学报1998年第3期

论文作者：李义春 樊建中 张奎 张少明 石力开 武高辉 孙东立 杨德庄

文章页码：399 - 404

关键词：颗粒增强铝基复合材料； 微屈服行为； 冷热循环处理

Key words：Al matrix composites； microyield behavior； thermal cycling treatment

摘    要：采用微屈服强度测试、 透射电镜和高分辨透射电镜分析，对经过不同冷热循环工艺处理后的颗粒增强铝基复合材料的微屈服行为进行了研究。结果表明，冷热循环次数虽然对颗粒增强铝基复合材料微屈服行为的宏观规律没有本质的影响，但是仍然影响颗粒增强铝基复合材料的微屈服行为。 对球形颗粒而言， 小应变量下的微屈服强度随冷热循环次数的增加而增高；但对棱形颗粒而言， 循环次数的影响较为复杂。 研究还表明， 冷热循环次数影响颗粒增强铝基复合材料微屈服行为的主要原因是其位错组态和残余应力在不同的循环次数下有明显的不同。

Abstract: An aluminum alloy(6061) matrix composite reinforced with 35% volume fraction of Al₂O₃ particles or SiC was fabricated by squeeze casting method. The Al₂O₃ particles are spherical, and SiC particles are angular. The microyield behavior of the composite was investigated, and the effect of different thermal cycling treatments on the microyield behaviors of the composite was studied. Based on TEM and HREM observations of microstructures, the mechanism of microyield behavior in the Al₂O₃p/6061 or SiC_p/6061 composites was analyzed. Results indicate that the microyield behavior of the particles reinforced aluminum matrix composites can be described by Brown-Lukens's theory which satisfactorily explained that of aluminium alloys and other light alloys, and is greatly affected by the different thermal cycling treatments. The more the numbers of thermal cycling treatments, the higher the microyield strength at small strains in the Al₂O₃p/6061. Thermal cycling treatment mainly affects the thermal mismatch stress and the density of movable dislocations in the matrix.