The effect of mechanical milling and sintering temperature on the hardness of aluminum/graphene composites

Study on the graphene reinforced metal matrix nanocomposite has been carried out by many researchers. Various methods have been used to process this nanocomposite. In this study, a 0.2 wt% graphene reinforced Al-3Cu nanocomposites processed using powder metallurgy method have been used to add 0.2 wt% graphene by the powder metallurgy method. At first, the small disks with 20mm in diameter and 10mm in height were made by cold pressing. The disks then were sintered at 510˚C and 490 ˚C. Then, to evaluate the effect of aging on the hardness of the alloys composite, they were subjected to T6 heat treatment. The effect of 0.2 wt% graphene and the mechanical alloying process on the microstructure of the samples were investigated by using optical microscopy(OM), and scanning electron microscopy(SEM). The hardness of the samples was determined using microhardness test method. The hardness of none heat treated composite increased about 16% due to the addition of 0.2 wt% graphene at 510˚C. Also, the hardness of the reinforced composite increased about 26% due to age hardening heat treatment compared to the none heat treated composite. In addition of the graphene, formation of an intermetallic compound of Al2Cu during the mechanical alloying has a reinforcing effect, and it increases the hardness. For this reason, the aging composite hardness is 32% higher than the alloy.

کلیدواژه ها:

graphene ، composite ، hardness ، powder metallurgy