Effects of shot-peening on stress corrosion cracking of non-combustible magnesium alloys weld.

Abstract

A base material, a welding sample and the welding samples treated shot-peening were prepared from wrought non-combustible magnesium alloy (AMX602) used for a welding structure, in order to reduce stress corrosion cracking at welding parts in the magnesium alloys. The samples were examined by 400 hours corrosion test at 35°C and 100% humidity with preload of 80% angle of break point. The results were as follows.
(1) The pitting corrosion without the stress corrosion cracking was observed on the base material. (2) The welding sample was observed the stress corrosion cracking in 200 hours corrosion test. (3) 0.2% proof stress of the welding sample was showed 12% decrease in comparison with that of the base material. (4) Stress corrosion cracking was suppressed by shot peening process to impart compression residual stress deeper than 100 μm. In this time, 0.2% proof stress of the species peened by shot was more than or equal to that of base material.