Method development for assessing stress corrosion cracking of magnesium alloy subassemblies

Magnesium alloys are lightweight structural materials that have attracted increasing attention in automotive structure and chassis applications, offering considerable potential for increasing vehicle efficiency. However, their inferior corrosion properties have been one of the major hurdles for their increased use in the automotive industry. In particular, these challenges arise due to the susceptibility of magnesium alloys to stress corrosion cracking under large service loads while in a salty environment. Standardized methods are needed for assessing the corrosion performances of magnesium alloys as entire subassemblies under service loading conditions. In this work, a specific loading rig was designed and fabricated to enable in-situ application of desired load on the automotive front-end subassembly during corrosion testing. Stress distribution on the subassembly under various loading levels was simulated. The subassemblies were subjected to cyclic corrosion tests under baded and load-free conditions. The work reports outcomes from a Canada-China-USA collaborative project, Magnesium Front End R&D (MFERD), currently underway.