Microstructural and impact toughness properties of a magnesium AM60B die cast alloy

An investigation about the effects of heat treatments on a Mg-Al-Mn alloy was carried out. Die cast AM60B alloy specimens were produced with a multispecimen die in a high-pressure cold-chamber apparatus and subjected to microstructural investigations, tensile tests and impact toughness tests. The specimens were either studied in their original as cast condition or they were subjected to a direct aging at 175 degreesC. A solution treatment was further considered to obtain the T4 temper and the T6 temper by a subsequent aging. The investigation allowed to evaluate modifications of microstructural and mechanical properties as a function of thermal treatments. Specifically, it was shown that despite the increase in void volume fraction and size induced by thermal treatments, a significant improvement of toughness during crack growth process could be achieved with an appropriate solution treatment.