Simultaneously enhancing the strength and ductility of particulate-reinforced aluminum matrix composite by aging treatment

In this work, powder thixoforming technique was utilized to prepare 10 vol% SiC particulate-reinforced 6061 alloy matrix (SiCp/6061Al) composite and artificial aging treatment was conducted to enhance mechanical properties. The results reveal that the aging process of SiCp/6061Al composite at 175 degrees C can be divided into three stages: under-aged (0.5-10 h) stage, peak-aged (10 h) stage and over-aged (10-48 h) stage, which were dominated by Guinier-Preston zone, beta '' and beta phase, respectively. Correspondingly, the tensile strengths of this composite exhibited a trend of first rising (0.5-10 h) and then decreasing (10-48 h), while the elongation continuously decreased all the time. Comparing with the as-fabricated composite, optimal aging treatment for 10 h led to maximum ultimate tensile strength of 309 MPa, yield strength of 240 MPa and a moderate elongation of 3.7%, representing remarkable increments of 34.3%, 87.5% and 42.3%, respectively. The aging behaviors of SiCp/6061Al composite and corresponding strengthening as well as toughening mechanisms were discussed. Graphic abstract