Mechanical properties and corrosion behavior of a ZK60 magnesium alloy containing profuse twins and precipitates

Abstract

The study utilizes a multi-directional compression (MDC) process on a basal-textured ZK60 alloy with the aim of inducing extensive twinning, which is followed by an aging treatment on the pre-deformed sample. The mechanical response and corrosion behavior of the deformed and aged samples are systematically investigated. The MDC process effectively generates numerous {10 1‾ 2} twins with increased compression passes, resulting in the enhanced grain refinement. The interplay between twins and numerous dislocations formed during pre-deformation plays a crucial role in altering both the distribution and morphology of the second phase precipitated during aging. During the aging process, the alloy exhibits a higher concentration of dense rod-like β′ phase and disk-like β″ phase. Remarkably, the compressive yield strength and ultimate strength of aged ZK60 alloy along the rolling direction are significantly improved without obvious compromise of ductility by pre-compression. Notably, the yield strength of the sample after 12-passes compression and aging (APD-12) is approximately 45 % higher than that of the sample without pre-compression (APD-0). Furthermore, the corrosion resistance of ZK60 alloy displays notable improvement upon pre-compression treatment. Specifically, the hydrogen evolution in the APD-12 sample is halved compared to the APD-0 sample. Electrochemical assessments were conducted on both pre-compressed and non-pre-compressed samples, revealing their distinct behaviors. Furthermore, an in-depth exploration has also been undertaken into the underlying mechanisms contributing to the enhancement of mechanical properties and corrosion resistance resulting from the pre-compression.

Keywords

• Mg alloys
• Deformation twins
• Mechanical property
• Corrosion behavior