半固态重熔加热工艺对镁合金组织与耐蚀性能的影响

摘要

The effects of semi-solid remelting heat treatment on the microstructure and corrosion resistancernof AZ91D magnesium alloys were detailedly carried out. The results show that the low-melting eutectic phasernprimarily melted and separated the α-Mg dendrites when AZ91D magnesium alloy was isothermally-treatedrnat the semi-solid temperature; then the large separate α-Mg dendrites evolved into the spherical grains andrneven merging growth occurred. The effects of remelting technological parameters on evolution process werernobvious.%详细研究了半固态重熔加热工艺参数对AZ91D镁合金半固态组织演变及其耐蚀性的影响.结果表明:AZ91D镁合金在液固双相区进行重熔处理时,合金中低熔点共晶组织首先发生熔化并隔离α-Mg树枝晶,其后被隔离的粗大α-Mg树枝晶逐步演化成为类球晶甚至发生合并长大现象.不同半固态重熔加热工艺参数对组织演化过程影响明显.