Elucidating the role of microstructural modification on stress corrosion cracking of biodegradable Mg-4Zn alloy in simulated body fluid

This paper investigates the effect of microstructure modification by heat treatment on stress corrosion cracking (SCC) behavior of Mg-4Zn alloy in simulated body fluid (SBF). Mg-4Zn alloy in as cast, solution heat treated and peak aged conditions was susceptible to SCC in SBF when strained at 3.6 x 10(-6) s(-1). SCC index based on fracture energy is least for solutionized alloy (0.84), while 0.88 for as cast and peak aged alloys. Fractographic analysis indicates predominantly intergranular SCC for solution treated alloy initiated by anodic dissolution near grain boundaries. As cast and peak aged alloy shows mainly transgranular failure due to hydrogen embrittlement adjacent to secondary phase particles.