Microstructure and Mechanical Properties of a Partially Recrystallized Aluminium Alloy having Varying Cu/Mg Ratio

Md. Jasim Uddin (Bangladesh University of Engineering and Technology Department of Materials and Metallurgical Engineering, Dhaka 1000, Bangladesh)
Hossain Rashed (Bangladesh University of Engineering and Technology)

Journal of Energy, Mechanical, Material and Manufacturing Engineering
Vol. 6 No. 2 (2021)

Heat treatable Al-Zn-Mg-Cu alloys are widely used in automobile industries, aerospace and military applications. This study investigates the effects of different amounts of copper and magnesium on microstructure and mechanical properties. The as-cast alloys prepared in a permanent mould showed a dendritic microstructure and the intermetallic phase surrounded by secondary phases. As-cast microstructure was refined substantially during hot rolling processes. The ultimate tensile strength and hardness values both in hot-rolled and aged conditions along longitudinal and transverse directions were found greater for the alloy containing 1.33 wt.% copper and 1.01 wt.% magnesium, whereas strain to fracture values for alloy 01 with 1.09 wt.% copper and 1.8 wt.% magnesium. The fracture surface of the tensile sample having relatively lower amount of copper content revealed dimple rupture behaviour, while higher 4.32 wt.% copper content indicated transgranular and cleavage fracture. A similar pattern was also observed along the transverse direction. Overall, copper appeared to be more effective in strengthening of the studied alloys.