SiC颗粒粒径对高压扭转SiC_P/Al复合材料致密度和拉伸性能的影响

Effects of SiC Particle Size on Density and Tensile Properties of High-pressure Torsion SiC_P/Al Composites

采用高压扭转法(HPT)将不同尺寸的SiC颗粒和工业纯Al混合粉末直接固结成形制备SiC_P/Al复合材料。利用排水法测量复合材料的体积并计算致密度,再通过拉伸试验及拉伸断口扫描电镜观察,研究SiC颗粒粒径对复合材料致密度和拉伸性能的影响。结果表明,在200℃下,由于SiC颗粒含量一定,随着颗粒尺寸的增大,颗粒数量减少,比表面积逐渐减小,大颗粒受剪切作用而发生破碎的趋势加剧,结合不牢固的新生界面增加,导致复合材料致密度和抗拉强度呈先升高后降低的趋势;同时拉伸断口处韧窝尺寸逐渐增大,分布均匀性降低,韧窝处残留颗粒增加,复合材料韧性断裂特征减弱,脆性断裂特征增强。

The mixture powders were directly consolidated of SiC particles with different size and industrial pure aluminum by high-pressure torsion（HPT）to prepare SiC_P/Al composites.The volume of the composites was measured with drainage method,and then the density was calculated.Effects of SiC particle size on density and tensile properties of the composites were studied by tensile tests and SEM observation of the tensile fracture.The results show that with the increase of SiC particle size at 200 ℃,both the amount and specific surface area of the particles gradually decrease due to the certain SiC particle content,more large particles are broken by shearing force and weakly bound freshmen interface increases,resulting in both the density and tensile strength of the composites increasing firstly and then decreasing.Meanwhile,the dimples in tensile fracture have increased size with poorer distribution uniformity,the residue particles in the dimple increase,and therefore the composites have weakened ductile fracture characteristics and enhanced brittle fracture characteristics.