定向凝固Al_2O_3/Al—4.5Cu复合材料显微组织与合金元素的分布

MICROSTRUCTURE AND ALLOY ELEMENT DISTRIBUTION OF DIRECTIONALLY SOLIDIFITED Al_2O_3/Al-4.5Cu METAL MATRIX COMPOSITES

利用ZMLMC定向凝固装置，研究了Al2O3／Al—4．5Cu金属基复合材料在不同凝固冷却速率条件下的显微组织和合金元素分布的变化，实验结果表明：当凝固速度v=16．7μm／s时，Al2O3／Al—45Cu复合材料基体组织为胞状晶，胞状晶中无颗粒存在；当v=49.8μm／s时，基体为树枝状晶，颗粒在枝品中均匀分布，一、二次枝晶间距随着凝固速度的提高而减小Cu元素在Al2O3／Al—45Cu复合材料的液／固界面前沿的分布状况随着生长速率的增大呈现规则性的变化.

The microstructure and the change of alloy elements distribution of Al2O3/Al-4.5 Cu composites have been studied by use of the newly developing ZMLMC directional solidification apparatus, experimental results showed: At solidification rate v=16.7 μm/s, the microstructure of directionally solidified Al2O3/Al-4.5Cu composites, was cell morphologies, there were no Al2O3 particles in the cell structures, as solidification rate was increased to 49.8μm/s, its microstructureswere dendrites morphologies, particles were uniformly distributed in dendrites; with increase of solidification rate, the primary and secondary dendrite arm spacings decreased, the distributionof Cu element in the vicinity of liquid-solid interface was also changed regularly.