Effect of cooling media temperature for solid solution treatment on as-aged microstructure and hardness of Mg-13Gd-4Y-2Zn-0.5Zr alloy

doi:10.13251/j.issn.0254-6051.2020.08.030

Abstract

Abstract: Effect of cooling media temperature for solid solution treatment under different parameters on as-aged microstructure and hardness of high rare earth Mg-13Gd-4Y-2Zn-0.5Zr magnesium alloy was studied by SEM, EBSD and Vickers hardness testing. The results show that when solution treated at 520 ℃×24 h, the cooling medium temperature has the most significant effect on the hardness and microstructure, and the hardness value increases gradually with the decrease of cooling media temperature. Moreover, the lower the cooling medium temperature, the more the dot-like Mg₅(Gd,Y) phase and lamellar phase are precipitated during aging. However, when the cooling media temperature is high, needle-shaped Mg₅(Gd,Y) phase is mainly precipitated, while the phases with stacking faults (SFs) are less. In addition, because the grain size of the alloy is not changed obviously under low temperature or short time solid solution treatment, the effect of refinement strengthening is higher than that of the precipitation strengthening in subsequent aging process, thus the cooling media temperature for solid solution treatment has a weak effect on the hardness and microstructure.

Key words: Mg-13Gd-4Y-2Zn-0.5Zr alloy, cooling media temperature for solid solution treatment, aging, microstructure, hardness

CLC Number:

TG166.4

Shi Zheng, Meng Mu, Yang Xue, Zhang Zhiming, Gao Zhi. Effect of cooling media temperature for solid solution treatment on as-aged microstructure and hardness of Mg-13Gd-4Y-2Zn-0.5Zr alloy[J]. Heat Treatment of Metals, 2020, 45(8): 156-160.

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