热处理对挤压铸造SiC_(p)/ZL101铝基复合材料组织与性能的影响

Effects of Heat Treatment on Microstructure and Properties of Squeezed Casting SiC_(p)/ZL101 Composites

通过半固态机械搅拌法和近液相线法制备了SiC_(p)(μm级)质量分数为3%的ZL101铝合金半固态坯料,对坯料二次加热后挤压获得SiC_(p)/ZL101铝基复合材料。研究了固溶和时效处理对复合材料显微组织和性能的影响。结果表明,挤压铸造制备的SiC_(p)/ZL101复合材料显微组织由近球形的α-Al、长条状的共晶Si组织,以及多边形的SiC颗粒组成。经过固溶处理后,共晶Si转变为近球状;时效处理后,基体和第二相界面的析出相数量增加,复合材料的抗拉强度、屈服强度和伸长率分别达到320 MPa、244 MPa和6.91%,显微硬度(HV)为114,复合材料的断裂形式由微孔聚集型断裂转变为准解理断裂。

3% micron-sized SiC_(p)/ZL101 semi-solid billet was prepared by semi-solid mechanical stirring and near liquidus method, and SiC_(p)/ZL101 composites were obtained by remelting and extrusion. The effects of solid solution and aging on the microstructure and properties of the composite were investigated. The results indicate that the microstructure of SiC_(p)/ZL101 composites is characterized by near spherical α-Al, elongated eutectic Si and polygonal SiC particles. After solid solution treatment, the eutectic Si is converted to nearly spherical one. After further aging treatment, the amount of precipitated phase is increased at the interface between the matrix and the second phase, and the tensile strength, yield strength, elongation and hardness of the composites reach up to 320 MPa, 244 MPa, 6.91% and 114 HV, respectively. The fracture morphology is transformed from microvoid accumulation fracture to quasi-cleavage fracture.