强流脉冲电子束处理对Al-20Si合金微观组织和显微硬度的影响

研究了强流脉冲电子束处理对过共晶铝硅合金Al-20Si组织结构和显微硬度的影响.通过扫描电镜和X射线衍射对改性表面的组织特征进行了分析.扫描电镜结果表明,在电子束所诱导的顶部熔化层中,初生硅溶解在铝基体中形成了铝硅过饱和固溶体.相邻初生硅颗粒由于硅元素的扩散融合成大的初生硅颗粒.X射线衍射分析表明电子束处理后铝的晶格常数下降,晶格畸变增加.显微硬度测试结果指出初生硅的表面硬度在电子束处理后从中心向边缘呈现梯度分布,并且初生硅的中心硬度随脉冲次数的增加而减小.这表明强流脉冲电子束技术在处理过共晶铝硅合金初生硅组织中有着良好的应用前景.

Effect of HCPEB treatment on microstructure and microhardness of hypereutectic Al-20Si alloy

Effect of high current pulsed electron beam (HCPEB) treatment on microstructure and microhardness of hypereutectic Al-20Si alloy was investigated.The microstructure characteristics of modified surface were analyzed by SEM and XRD.SEM results show that primary Si is dissolved in Al matrix and Al supersaturated solid solution is formed on top of the melted layer induced by HCPEB treatment.It can be seen that adjacent primary Si particles merge one large primary Si particle due to diffusion of Si element.XRD analysis shows that the lattice parameters of Al decrease and lattice strain increases after HCPEB treatment.Microhardness test results show the surface microhardness of primary Si presents gradient distribution from the center to edge after HCPEB treatment,and the microhardness of center of primary Si decreases with increase of pulse number.It is demonstrated that the HCPEB technique has a good application future in refining coarse primary Si of hypereutectic Al-Si alloys.