Processing and performance of magnesium die castings

Abstract

Magnesium die castings have many applications in automotive, aerospace and electronic industries, because of their lightness, castability, recyclability and electro-magnetic radiation shielding capability. However, an important characteristic of magnesium that influences its development is its poor corrosion resistance. The aim of this thesis was to investigate the performance of AM60B and AZ91D magnesium die castings, including processing, microstructure and particularly the corrosion and stress corrosion cracking. Stress corrosion cracking of AZ91D die castings in 5% NaCl and 5% NaCl + 5% K2CrO4 was investigated using constant load tensile test and electron microscopy. It was found that the fracture mode was mainly transgranular. The time to failure is short at the applied stress of 60% UTS and tends to increase with decreasing applied stress level.