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采用扫描电镜、X射线衍射仪、拉伸试验机、涡流导电率仪等实验手段,研究质量分数为0~0.25%的Y对Al-2.5%Cu合金铸态组织和性能的影响。结果表明,Y加入Al-2.5%Cu合金中主要形成Al6Cu6Y与Al3Y相弥散分布在晶界上,且Y可以显著细化α-Al枝晶并减小二次枝晶间距,但随着Y含量的增加,导电率呈平缓下降趋势;Y加入量小于0.20%时,随含量增加细晶作用明显;当Y含量为0.20%时,铸态合金组织中晶粒细化效果最为显著,晶粒尺寸减小至30μm左右,第二相出现球化现象,力学及耐热性能达到峰值;当Y加入达到0.25%时,晶粒粗化,力学及耐热性能下降。
The effects of Y with mass fraction of 0 ~ 0.25% on the as-cast microstructure and properties of Al-2.5% Cu alloy were investigated by scanning electron microscopy, X-ray diffraction, tensile testing and eddy current conductivity testing. The results show that the Al6Cu6Y and Al3Y phases are mainly dispersed in the grain boundary in Y-added Al-2.5% Cu alloy, and Y can remarkably refine the α-Al dendrite and reduce the secondary dendrite spacing. However, with Y content , The electrical conductivity showed a gentle downward trend; when the content of Y was less than 0.20%, the fine grained effect was obvious with the content increasing; when the Y content was 0.20%, the grain refinement effect was the most significant in the as-cast alloy microstructure. The grain size When the content of Y reaches 0.25%, the grains coarsen and the mechanical and heat-resistant properties decrease.