Effect of solution treatment on microstructure and corrosion resistance of Mg-1Zn-1Ca alloy

doi:10.13251/j.issn.0254-6051.2023.09.008

Abstract

Abstract: Microstructure evolution of as-cast Mg-1Zn-1Ca alloy after solution treatment was studied by means of OM, SEM, EDS and XRD, and the effect of solution treatment on the corrosion resistance of the alloy was explored by electrochemical experiments and immersion experiments. The results show that the as-cast Mg-1Zn-1Ca alloy is composed of Mg matrix, Ca₂Mg₆Zn₃ phase and Mg₂Ca phase, while after solution treatment, the matrix grains gradually grow with the increase of solution temperature (400, 420, 440 ℃), the Ca₂Mg₆Zn₃ phase redissolves, the amount of second phases gradually decreases, the corrosion rate of the alloy first decreases and then increases. The alloy has the best corrosion resistance after solution treatment at 420 ℃ for 8 h, with the lowest average corrosion rate of 0.7725±0.016 mm/y. The improvement of corrosion resistance is attributed to the second phase redissolution, and the galvanic corrosion effect is weakened. While for the alloy after solution treatment at 440 ℃ for 8 h, the corrosion resistance deteriorates because the grain coarsening intensifies the local corrosion.

Key words: Mg-1Zn-1Ca alloy, solution treatment, second phase, corrosion resistance

CLC Number:

Wang Jian, Song Lei, Wang Yizhuo, Zhang Quanfu, Ren Naidong, Wu Weikang, Wang Hongxia, Luo Xiaoping. Effect of solution treatment on microstructure and corrosion resistance of Mg-1Zn-1Ca alloy[J]. Heat Treatment of Metals, 2023, 48(9): 48-53.

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