Some aspects of Cold Deformation studies of Al-ZrB2 composites

In the present study Al-ZrB2 composite were made by powder metallurgy route adding different amounts of synthesized ZrB2 powder (2, 4, 6, 8, 10 wt. %). The ZrB2 powder was synthesized by using self-propagating high temperature synthesis (SHS). The samples of different aspect ratios (0.35, 0.5 and 0.65) were made and then sintered at 550oC under continuous argon gas atmosphere in a tubular furnace for 1 hour. The microstructure of the composites had shown that there is no chemical adhesion between Al matrix and ZrB2 reinforcement. Hardness of the composites increased with increase in the amount of ZrB2 reinforcement. The hardness of the composites increased with increase in amount of ZrB2 reinforcement. It was found that the formability stress index increased with the increase of preform fractional density and decreased with the aspect ratio. Relation between various stress ratios, axial strain and relative densities were analyzed. Statistical fitting methods are used on the curve drawn between the axial strain and the stress formability index. The compacts of lower aspect ratio and high initial preform density were found to have a very high fracture strain.