Microstructural and mechanical characterization of magnesium based alloy MA14 (ZK60 A): Evolution under deformation and heat treatment

Abstract

The interest in magnesium based alloys as structural metal material is due to their low weight, good mechanical and technological properties, high special strength, etc. So magnesium base alloys can compete successfully in physical and mechanical characteristics with other light structural materials especially in the fields where decrease in the mass is of primary significance. The aim of the present work was to study the influence of phase and structural changes in the main properties of commercial magnesium based alloy MA14 (ZK60 A) under deformation and heat treatment parameters. The microstructure was investigated with the use of an optical inverted microscope. The phase composition was investigated by chemical phase analysis with an X-ray analysis of each insulated phase. It is found, that there are primary phases Mg2Zn3, ZrZn2 and Zr3Zn2. Sometimes phases ε-ZrH2,δ-ZrH, Zr2Al can be present in phase composition. All the phases are the hardening ones. The phase quantity, size, morphology correlate with the condition of the magnesium alloy so traditional deformation and heat treatment has not had much influence on qualitative phase composition; only on the phase and grain size. Now it is stated that the most effective processing for receiving the elevated alloy properties is hydrostatic extrusion. The final operation of hydrostatic extrusion of magnesium alloy semi products causes the well-disposed structure and phase changes. Thus the high strength properties of the cheap commercial magnesium alloy MA14 are obtained: tensile strength is more than 380 MPa; tensile yield strength is more than 340 MPa. © 2014 WIT Press.