Microstructures and mechanical properties of in-situ Al3Ti/2024Al composites after solution and subsequent aging treatment

In the present work, in-situ Al3Ti/2024Al composites with different amount of Al3Ti reinforcements were fabricated by ultrasonic casting method. The effects of solution and subsequent aging treatment on the microstructures and mechanical properties were studied. The results show that solution at 500 °C for 6 h is suitable for in-situ Al3Ti/2024Al composites with mass fractions of reinforcements between 4 wt% and 16 wt%. The aging kinetics of Al3Ti/2024Al composites was promoted by the Al3Ti reinforcements. When the mass fraction of Al3Ti is increased from 0% to 16%, the peak hardness is increased by 20.3%, and the time required to reach the peak hardness is shortened by 66.7%. The microstructures of peak-aged Al3Ti/2024Al composites consist of equiaxed α-Al grains and evenly distributed reinforcing particles. As the mass fraction of Al3Ti increasing, the compression and tensile strengths were both increased gradually at the sacrifice of plasticity.