中文摘要：

采用强流脉冲电子束（HCPEB）技术对真空感应熔炼法制备的Cu-25Cr合金进行表面改性处理,所选用的脉冲次数范围为1~100。采用扫描电镜和X射线衍射技术对HCPEB处理前后样品表面的形貌和显微组织进行研究。结果显示,当脉冲次数增加到10次后,样品表面形貌会发生显著变化。在HCPEB处理过程中所产生的动态温度场使Cu-25Cr合金表面形成典型的熔坑组织。同时,该过程中所累积的准静态热应力场导致样品表面出现微裂纹,其数量随脉冲次数的增加而增大。另外,HCPEB处理还使Cu-25Cr合金表面发生液相分离现象,产生大量细小的Cr球。在上述特征组织的综合作用下,样品表面的粗糙度随脉冲次数的增加而增长。

英文摘要：

A Cu-25Cr alloy prepared by vacuum induction melting method was treated by the high current pulsed electron beam （HCPEB） with pulse numbers ranging from 1 to 100. Surface morphologies and microstructures of the alloy before and after the treatment were investigated by scanning electron microscopy and X-ray diffraction. The results show that significant surface modification can be induced by HCPEB with the pulse number reaching 10. Craters with typical morphologies on the Cu-25Cr alloy surface are formed due to the dynamic thermal field induced by the HCPEB. Micro-cracks, as a unique feature, are well revealed in the irradiated Cu-25Cr specimens and attributed to quasi-static thermal stresses accumulated along the specimen surface. The amount of cracks is found to increase with the pulse number and a preference of these cracks to Cr phases rather than Cu phases is also noted. Another characteristic produced by the HCPEB is the fine Cr spheroids, which are determined to be due to occurrence of liquid phase separation in the Cu-25Cr alloy. In addition, an examination on surface roughness of all specimens reveals that more pulses will produce a roughened surface, as a result of compromising the above features.