Find in Library

Aluminum matrix composites reinforced by <i>in-situ</i> Al₃Ti particles were successfully synthesized from an Al-Ti system <i>via</i> a direct melt reaction. The influences of Ti additions, ultrasonic time and power on the microstructure and mechanical property of composites were systematically investigated. The results show that the Al₃Ti particles are refined obviously and the distribution also becomes more uniform with the increase of ultrasonic power. Meanwhile, the addition of Ti refines the α-Al dendrite phases in the matrix, which gradually changes from the original coarse to fine branch crystals, rose-like or nearly spherical. However, results also show that the size of Al₃Ti particles decreases to a minimum value and then increases with the increase of ultrasonic time. The trends of the mechanical properties are consistent with the microstructures of the Al₃Ti/ADC12 composites. The optimum parameters of the composite are 3%Ti (mass fraction) content, 1.5kW ultrasonic power, 20kHz ultrasonic frequency and 6min ultrasonic time. Accordingly, the tensile strength and elongation of the composite synthesized reach to 247.34MPa and 2.31% respectively, increasing by 21.3% and 50.0% compared with the unmodified alloy.