Processing and Characterization of Magnesium Alloys and Composites By Powder Metallurgy Technique

Abstract

ABSTRACT newlineIn this research, two magnesium alloys were developed by powder metallurgy technique and optimized using Taguchi based grey method. The optimized magnesium alloy compositions were reinforced with different weight fractions of SiC and the effect of addition of SiC on mechanical properties with different strain rates were studied. Mg-Zn-Cu-Mn alloy and Mg-Zn-Sn-Mnalloy were optimized by varying the weight fractions of alloying elements using Taguchi based grey method. The optimal compositions of Mg-3Zn-1Cu-0.7Mn (ZC31) Mg alloy and Mg-3Zn-3Sn-0.3Mn (ZT33) Mg alloy were obtained. ZC31/SiC composite and ZT33/SiC composites were developed by powder metallurgy technique followed by hot extrusion and the mechanical properties were studied using 0.005s-1, 0.016s-1, and 0.05s-1 strain rates. The density of the composite increased with increase of SiCweight fraction because of increased percentage of denser SiC particles. Reduced porosity levels obtained in both the ZC31/SiC and ZT33/SiC composites due to post sintering hot extrusion. The effect of addition of SiC to the ZC31 Mg alloy matrix improved the micro hardness, UTS and UCS of ZC31/SiC composites. Fracture study reveals ductile fracture followed by transcrystalline fracture observed with the increase of SiC weight fraction as well as strain rate in the ZC31/SiC Mg composites. The effect of addition of SiC to the ZT33 Mg alloy matrix also improved the micro hardness, UTS and UCS of ZT33/SiC composites. Fracture of ZT33 Mg alloy and ZT33/SiC composite were followed cleavage and quasi-cleavage. newline