Spark plasma sintering of a high-energy ball milled Mg-10 wt% Al alloy

Abstract

The influence of spark plasma sintering (SPS) temperature on microstructure, hardness and corrosion behavior of a high-energy ball milled Mg-10 wt% Al alloy was investigated in this work. The holding time and sintering pressure for SPS were kept constant while varying the sintering temperature from 200 to 350 °C. The grain size and microstructure were studied using X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and Archimedes’ based density measurement. Corrosion behavior was investigated using potentiodynamic polarization tests. The nanocrystalline regime (grain size < 100 nm) was maintained even after SPS up to 350 °C. The density of the alloy increased with increasing the SPS temperature. Vickers’ hardness and corrosion performance improved up to 300 °C followed by a decrease after SPS at 350 °C. Possible reasons for densification, strengthening, and corrosion behavior have been discussed in the light of reduced porosity and microstructural changes.

Keywords

• Nanocrystalline alloy
• Magnesium
• High energy ball milling
• Spark plasma sintering
• Corrosion