Effect of Al-5Ti-0.8C Master Alloy on Microstructure and Elevated Temperature Mechanical Properties of Al-Cu-Mn Alloy

A new kind of Al-5Ti-0.8C master alloy was fabricated using a self-propagating combustion reaction method and dilution treatment, and the effects of different Al-5Ti-0.8C master alloy contents (0wt%, 0.1wt%, 0.3wt%, 0.5wt%) on the microstructure and elevated temperature mechanical properties of Al-Cu-Mn alloy were investigated. The results show that the Al-5Ti-0.8C master alloy refines the Al-Cu-Mn alloy, increases the amount of theta'(Al2Cu) precipitates, and reduces their size during heat treatment, resulting in the grain refinement. Moreover, this new master alloy obviously improves the elevated temperature mechanical properties of Al-Cu-n alloy, mainly due to the precipitation strengthening caused by the uniform distribution of second phases and fine theta'(Al2Cu) precipitates, and the formation of Al-3(Ti, Zr) nanoparticles with high thermal stability. Furthermore, the microstructure and mechanical properties of Al-Cu-Mn alloy with 0.3wt% A1-5Ti-0.8C master alloy show the optimal status.