LAUSR

Abstract The corrosion behaviors of as-cast and as-rolled Mg-6Bi-2Sn alloys were investigated in the simulated body fluid solution, and the influence of the microstructural characteristics on the corrosion properties were discussed. The as-cast alloy mainly consists of α-Mg and Mg 3 Bi 2 phases, while a new Mg 2 Sn phase can be observed in as-rolled one. In addition, the average dendrite arm spacing and average second phase particle size of the as-cast alloy was 27.23 ± 2.14 μm and 9.89 ± 0.76 μm, respectively. After rolling, remarkable grain refinement and uniform distribution of second phase particles could be achieved with the average size of grains and second phase particles being 11.28 ± 1.12 μm and 1.84 ± 0.08 μm, respectively. The electrochemical and immersion tests results indicated that the as-rolled alloy have a lower corrosion rate than the as-cast one. The remarkably deceased corrosion rate of as-rolled Mg-6Bi-2Sn alloy in simulated body fluid solution is mainly attributed to refined grain size, finely dispersed secondary phase particles, favorable crystal orientation and the formation of passivity film.