The origin of high-density dislocations in additively manufactured metals

作者：Ge Wang, Heng Ouyang, Fan Chen, Qiang Guo, Zhiqiang Li, Zhiqiang Li, Wentao Yan, Zan Li, Zan Li · 发表于：Materials Research Letters · 年份：2020 · DOI：10.1080/21663831.2020.1751739 · 被引用次数：400 · 研究领域：Additive Manufacturing Materials and Processes、Welding Techniques and Residual Stresses、High Entropy Alloys Studies

The origin of dense dislocations in many additively manufactured metals remains a mystery. We here employed pure Cu as a prototype and fabricated the very challenging high-purity (>99.9%) bulk Cu by laser powder-bed-fusion (L-PBF) technique. We found that high-density dislocations were present in the as-built samples and these high-density dislocations were introduced on the fly during the L-PBF process. A newly developed multi-physics modeling was further employed to interpret the origin of these pre-existing dislocations, demonstrating that the compression-tension cycles rendered by the localized heating/cooling heterogeneity upon laser scanning are responsible for the residual high-density dislocations.