超显微硬度法研究SiC_P/6066铝基复合材料微区硬度变化

Study of micro-zone mechanical properties of SiC_P/6066 composites by the method of ultra-microhardness

对喷射共沉积后经挤压的SiCP/ 6 0 6 6铝基复合材料 ,通过采用超显微硬度法测量了其微区的硬度变化 ,观察其显微组织 .结果表明 :在SiC颗粒分布密集处 ,基体超显微硬度值HV为 143.2 ,而在SiC颗粒分布稀疏处 ,硬度值HV为 10 7.2 ,二者之间有明显差距 .这是由于分布密集的增强体SiCP 周围局部基体应力场应力集中更剧烈而使超显微硬度值提高 .此外还测量了由于热收缩应力引起SiCP 周围应力场的变化而导致的微区硬度的变化 .在SiC颗粒附近基体硬度值较高 ,HV达 10 5 .8,而离SiC粒子距离大于其颗粒半径的基体中 ,硬度较低 ,HV约为 81.7.SiCP 造成基体中应力场的叠加可使基体中出现张应力区 .此外 ,通过测量复合材料超显微硬度值的变化 。

The hardness variations in the micro zone of SiC P/6066 Al composites prepared by multi layer deposition were measured by ultra microhardness technique, and the microstructure of such composites was observed using optical microscope. The results show that the ultra microhardness in the micro zone of matrix, where the SiC P distributed densely, is 143.3 HV, but the hardness is only 107.2 HV where the SiC particles distributed sparsely. The thermal residual strain in the matrix near the interface of the reinforcer and the matrix results in strain hardening of the matrix. The hardness value is 105.8 HV around particles and only 81.7 HV in the matrix. The variation of ultra microhardness reflects the distribution of residual strain in the matrix, especially in the micro zones. All this information is helpful to understand the deformation rule of SiC P/6066 Al composites.