Effect of ultrasonic vibration and solution-aging treatment on microstructure and properties of in-situ TiAl₃/7050Al composites

Ultrasonic vibration have positive effect on formation of in-situ TiAl₃/7050Al composites, the role of ultrasound in the reaction process was described systematically. The best solution-aging treatment parameters were discussed and effects of the selected treatment on the resultant microstructure and mechanical properties were investigated. The results show that ultrasonic vibration not only promote the reaction process, but also result in significant spreading particles fallen off from the reaction interface, therefore creating a finer and homogeneous distribution of TiAl₃ particles in the composite. In solution process, the skeleton second phase dissolve into matrix with increasing temperature and holding time, the transformation is more sensitive to solution temperature. Residual second phase transform into finer-size rod or discoid shape and a large amount of finer phase (MgZn₂ and CuAl₂)precipitates after aging-treated. As a result, the strength, hardness and elongation of the composite are slightly increased after using ultrasonic vibration and significantly increased after solution-aging treatment.