Effect of Stirring on the Microstructure and Mechanical Properties of ZAMAK-12 Alloy

Abstract

Zinc alloy ZAMAK-12 was melted in an induction melting process. The melted alloy was stirred mechanically at 400±10 oC for 5 minutes using a cast iron mixer. The speed of stirring was 1500 rpm. After stirring the melt was casted in a mold made from graphite immediately and quenched with water. The microstructures of unstirred and stirred samples were investigated with optical microscopy. The hardness’ of samples were measured with Vickers indenter. The strengths of samples were determined by compression testing. The microstructural investigations showed that both stirred and unstirred ZAMAK-12 alloys have a dendritic microstructure. But, the grain size of Al-rich dendrites was finer and longer into the stirred samples. The hardness of stirred ZAMAK-12 was slightly higher than unstirred alloy. The compression yield strength and Elastic Modules of the stirred sample was lower than unstirred alloy, whereas the compression yield strain of the stirred alloy was higher.