Abstract
This study investigated the effect of copper addition on AA-7075 aluminum alloy's microstructure and mechanical behavior. Aluminum alloy with copper reinforcement varying between 0.3 and 0.7 wt.% was produced using the stir casting technique. The cast aluminum alloy was pre-heated at a temperature of 300 °C and held for 1 h before charging into the bale-out furnace. Two AA-7075 + Cu alloy samples were produced at a different weight percent of copper. Both pre-heated and the as-received aluminum samples were subjected to mechanical testing after machining. The surface morphology of the samples was studied using optical and scanning electron microscopy. The relevance of the percentage weight of copper in the aluminum alloy cannot be over-emphasized and strategic in the food processing and packaging industries. The result showed that the higher the addition of Cu the harder the composite becomes. The microstructures showed distinct grain boundaries for AA-7075 aluminum alloy while rich regions of silicon saturation were observed for 0.7 wt.% Cu in AA-7075 and 0.3 wt.% Cu in AA-7075 alloy. The AA-7075 alloy samples with 0.7 wt.% copper and 0.3 wt.% copper had their respective tensile strength as 0.18 Mpa and 0.15 Mpa and hardness value as 420Hv1 and 240HVv1. The tensile strength of the cast samples was positively influenced by the addition of copper with well-distributed reinforcing intermetallic phases which are fine grain size, although there is an observable reduction of micro-segregation. Thus, enhancing the mechanical properties of the alloys of the developed composites.