Effects of RE and Sr additions on dendrite growth and phase precipitation in AZ91D magnesium alloy
来源期刊：中国有色金属学报(英文版)2010年增刊第2期
论文作者：周吉学 王杰 王晶 杨院生
文章页码：331 - 335
Key words：magnesium alloy AZ91D; strontium (Sr); rare earth; grain refinement; precipitation; dendrite growth
Abstract: To develop AZ91D alloys with fine microstructure, effects of the addition of rare earth (RE), Sr and RE + Sr on the dendrite growth and phase precipitation in AZ91D magnesium alloy were studied, respectively. The results show that the microstructure is refined and the morphology of β-Mg17A112 phase is modified with RE or Sr addition, especially with the RE+Sr composite addition which can reduce the average grain size of AZ91D alloy obviously to 141 μm. The needle-like or block-like new phases adhering to β-Mg17A112 phase form at interdendrites during solidification. The enrichment of RE or/and Sr elements in front of the solidification interface, especially at the tips of α-Mg dendrite, which restricts the growth of α-Mg dendrite, changes the preferential growth of α-Mg and finally results in the grain refinement and the blunting of α-Mg dendrite.
基金信息：the National Natural Science Foundation of China
the National Basic Research Program of China
