SiC纳米颗粒增强A356铸造合金的表征

摘要

The microstructure and mechanical properties of nano composites processed via stir casting were studied.The composites were based on the A356 aluminum alloy reinforced with nano SiC particles.The density measurements show that the samples contain little porosity and the amount of porosity in the composites increases with increasing volume fraction of SiC.The microstructures of the composites were examined using optical microscope and transmission electron microscope.Microscopic observations of the microstructures reveal that the dispersion of the particles is uniform.The yield strength,ultimate tensile strength and the elastic modulus are improved with the addition of nano particles although some reduction in ductility is observed.The highest yield strength and ultimate tensile strength are obtained with the addition of 3.5％ SiC nano-particles.A relatively ductile fracture in tensile fractured samples was observed by fractography examination.%通过搅拌铸造制备SiC纳米颗粒增强A356铝合金复合材料,并研究其显微组织和力学性能.密度测量发现试样的孔隙度较低,且孔隙度随SiC颗粒体积分数的增加而增加.通过光学显微镜和透射电镜观察材料的显微组织,发现弥散的颗粒分布均匀.材料的拉伸强度和弹性模量随加入纳米SiC颗粒的增加而提高,而延展性有所降低.当SiC纳米颗粒的加入量为3.5％时,复合材料的屈服强度和极限抗拉强度达到最高.断口分析表明,拉伸断裂试样为相对韧性断裂.