Development of rapidly solidified (RS) magnesium–aluminium–zinc alloy

Applications of magnesium alloys in the aerospace industry are limited because of their poor mechanical properties, corrosion resistance and workability. Refinement of microstructure through rapid solidification processing is one of the highly potential approaches to overcome these limitations. In the present study, the technology of processing of rapidly solidified (RS) ribbons in Mg-9%Al-1%Zn-0.2%Mn alloy has been established using melt spinning technique. The effect of wheel speed on thickness and microhardness of the ribbons is presented. Microhardness is found to increase with the wheel speed. It is further observed that microhardness of the ribbons increases with the heat treatment temperature upto 200°C and thereafter it starts decreasing. Precipitation of the intermetallic phase Mg17Al12, at temperatures upto 200°C is found to prevent the grain growth and improve the properties of the ribbons. This in-turn reveals that the temperature for secondary processing of RS ribbons in Mg-9%Al-1%Zn-0.2%Mn alloy should not exceed 200°C in order to retain the benefits of rapid solidification processing.