时效处理对Mg-5Sn-1Si合金显微组织和硬度的影响

研究时效温度、保温时间对Mg-5Sn-1Si合金显微组织和硬度的影响,分析时效处理的作用机制。结果表明,保温时间一定时,随温度升高,晶粒球化程度加强,析出相数量逐渐增加。温度一定的条件下,随保温时间延长,合金组织先后经过不连续析出、连续析出与网状析出三种变化,当保温时间较长时,第二相颗粒发生偏聚。合金经过时效处理后,显微硬度得到明显改善,比相应的铸态合金高出20%,随时效温度升高和保温时间延长,合金硬度均出现先升高后降低的趋势。

Effects of Aging Treatment on Microstructure and Hardness of Mg-5Sn-1Si Magnesium Alloy

In this paper, the effects of aging temperature and soaking time on the microstructure and hardness of Mg-5Sn-1Si alloy were studied, and the mechanism of aging treatment was analyzed in theoretically. The results show that with certain soaking time and the increase of aging temperature, the spheroidization of grains strengthens, and the number of precipitated phase gradually increases. When heating temperature keeps constant, the structure has three kinds of situation with the extension of soaking time, they are discontinuous precipitation, continuous precipitation and reticular precipitation. WhenStheSsoakingStimeSis longer, the secondary phase particles aggregate. After aging treatment, the hardness of alloy gets improving obviously, about 20% higher than as-cast alloy, with the increase of temperature and the extension of time, its hardness all presents a trend of increased first and then decreased.