摘要
通过对等温热处理温度和保温时间等工艺参数的控制,研究变质剂Al-Ti-B对AZ91D镁合金半固态等温热处理组织的影响。结果表明:随着等温时间的延长,未变质处理的镁合金组织将由树枝晶变成近球状组织,变质处理的镁合金组织将由树枝晶变成细小的球状组织,都将逐渐的合并长大。保温温度越高,半固态重熔和α相演变过程越快,粗化长大后,晶粒间的合并现象越严重;保温温度过高或保温时间过长,试样易发生变形,同时,球状晶粒也容易趋于长大。但经过Al-Ti-B变质处理,其组织越细,越易获得良好的非枝晶组织,需要热处理的时间越短或温度越低。
The effect of Al-Ti-B on Semi-solid isothermal heat-treatment microstructure was investigated by controlling the heat treatment temperature, holding time and other parameters. The results show that with the increase of the holing time, the microstructure of magnesium alloy without modification is transformed from dendrite to near sphere, and the, microstructure of the modified magnesium alloy change from dendrite to fine sphere. In both cases, the grains will gradually grow up and merge. Higher the holding temperature, More fast the evolution of the α-phase and semi-solid remelting, when they grow up, the worsen merger between the grains appears; the much higher holding temperature or too long holding time cause the sample deformation easily, and the spherical grains tend to grow up as well. However, after modification of of Al-Ti-B, the finer microstructure can easily obtain non-dendritic structure, and the shorter holding time or the lower heat treatment temperature.
出处
《铸造技术》
CAS
北大核心
2009年第2期194-198,共5页
Foundry Technology
基金
国家973计划资助项目(2007CB613700)
兰州理工大学博士基金(SB01200412)
