Evolution of surface microstructure of Cu-50Cr alloy treated by high current pulsed electron beam
Evolution of surface microstructure of Cu-50Cr alloy treated by high current pulsed electron beam
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DOI：
10.1007/s11431-015-5774-7
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
L. Chai;Zhi-ming Zhou;Zhipei Xiao;J. Tu;Yaping Wang;Wei-jiu Huang
中科院分区：
文献类型：
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作者：
L. Chai;Zhi-ming Zhou;Zhipei Xiao;J. Tu;Yaping Wang;Wei-jiu Huang
采用20和30 keV、脉冲数1 ~ 100的强流脉冲电子束（HCPEB）对Cu-50 Cr合金进行了表面处理。采用扫描电子显微镜和X射线衍射分析了处理前后试样的表面形貌和微观结构。结果表明，高压脉冲电子束技术能够对Cu-50 Cr合金进行显著的表面改性。Cr相中的裂纹甚至在单脉冲处理后出现，并且它们的密度总是随着脉冲数而增加。这些裂纹的形成原因是由于准静态的热应力沿试样表面沿着积累。具有典型形貌的坑形成由于由HCPEB诱导的动态热场，他们被发现更喜欢的网站附近的裂纹或相邻的Cr相之间的边界。HCPEB产生的另一个显微组织特征是细小的Cr球状体，这被确定为是由于Cu-50 Cr合金中发生液相分离。最后，一个一般的微观结构的演变概况，结合各种HCPEB诱导的表面特征初步概述。
A Cu-50Cr alloy was treated by the high current pulsed electron beam (HCPEB) at 20 and 30 keV with pulse numbers ranging from 1 to 100. Surface morphologies and microstructures of specimens before and after the treatments were investigated by employing scanning electron microscopy and X-ray diffraction. Results show that the HCPEB technique is able to induce remarkable surface modifications for the Cu-50Cr alloy. Cracks in Cr phases appear even after one-pulse treatment and their density always increases with the pulse number. Formation reason for these cracks is attributed to quasi-static thermal stresses accumulated along the specimen surface. Craters with typical morphologies are formed due to the dynamic thermal field induced by the HCPEB and they are found to prefer the sites near cracks or boundaries between neighboring Cr phases. Another microstructural 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-50Cr alloy. Finally, a general microstructural evolution profile that incorporates various HCPEB-induced surface features is tentatively outlined.