研究了Ce对AZ31镁合金铸态组织的影响。研究结果表明：添加0.5~1.5 wt%Ce到AZ31镁合金中不但不能细化合金的晶粒，反而使合金的晶粒变得粗大，并且粗化趋势受Ce加入量的影响较大。当添加0.5 wt%Ce到AZ31镁合金中后，合金的平均晶粒尺寸从最初的60 μm增大到164 μm。此后，随着Ce加入量从0.5 wt% 增加到1.5 wt%，合金的平均晶粒尺寸又开始逐渐减小，但仍大于未添加Ce合金的平均晶粒尺寸。

Various opinions still exist regarding the grain refinement of magnesium alloys resulting from Ce addition. We investigate effect of Ce addition on the ascast microstructures of AZ31 magnesium alloy. The research results indicate that adding from 0.5 wt% to 1.5 wt% Ce to AZ31 magnesium alloy does not effectively refine the alloy grains; instead, the opposite effect results, causing obvious grain coarsening. The coarsening trend is related to the amount of Ce. After adding 0.5 wt% Ce to AZ31 magnesium alloy, the average alloy grain size increases from 60 μm to 164 μm. Furthermore, increasing the amount of Ce added from 0.5 wt% to 1.5 wt% causes the average grain size to decrease gradually. The average grain size of AZ31 magnesium alloy with and additional 1.5 wt% Ce still exceeds that of the AZ31 magnesium alloy without additional Ce, however.

国家973计划资助项目（2007CB613704）；国家杰出青年基金资助项目（50725413）