热处理工艺对AZ80镁合金组织和硬度的影响

Effect of Heat Treatment Process on Microstructure and Hardness of AZ80 Magnesium Alloy

挤压态AZ80镁合金分别在380、410、440℃固溶处理2h,固溶后的部分镁合金分别进行单级时效及双级时效处理。研究了固溶温度、单级时效及双级时效处理对AZ80镁合金组织和硬度的影响。结果表明:随固溶温度的升高,β-Mg_(17)Al_(12)共晶组织逐渐分解溶入α-Mg基体中,合金硬度也随之升高,440℃时晶粒变粗大;单级时效处理后,β-Mg_(17)Al_(12)相以连续和非连续的形式从α-Mg基体中析出,导致硬度大幅提高;双级时效处理后,β-Mg_(17)Al_(12)相的析出数目更多,尤其是晶内β-Mg_(17)Al_(12)相的连续析出,最高硬度能达到88.32 HV。

Solid solution treatment of extruded AZ80 magnesium alloy was carried out respectively at 380, 410 and 440 ℃ for 2h. The single and two-stage aging treatments for the partial magnesium alloy after the solid solution were carried out. The effects of solution temperature, single stage aging and two-stage aging treatment on microstructure and hardness of AZ80 magnesium alloy were investigated. The results indicate that with the increase of solid solution temperature, β-Mg17TA12 eutectic gradually is dissolved into the α-Mg matrix, and the hardness of the alloys also increases, but the grain sizes become coarse at 440℃; after single stage aging treatment, the β-Mg17Al12 phase is separated out from α-Mg matrix in the continuous and discontinuous form, which leads to a greatly increase in hardness; after the two-stage aging treatment, the precipitation number of β-MgtTAl12 phase is more, especially continuous precipitation of the β-Mg,7Al12 phase. Maximum hardness can reach 88.32HV.