Xin Chenxing, Zhao Xiya, Geng Haoze, Hao Liang, Li Yan, Chen Tao, Gong Ping
Gemmological Institute, China University of Geosciences Wuhan 430074 P. R. China.
Advanced Manufacturing Centre, China University of Geosciences Wuhan 430074 P. R. China
RSC Adv. 2023 Jan 24;13(6):3448-3458. doi: 10.1039/d2ra05965g.
Selective laser melting (SLM) technique is a viable alternative to fabricating metal matrix composites (MMCs) with controllable structures; however, its implementation remains challenging because of the unpredicted defects arising from the reinforcement. This study primarily examined the microstructural evolution and grain growth in the Ag-Cu/diamond composites at the molten pool scale during the SLM process a thermodynamic analysis. The feasibility of manufacturing Ag-Cu/diamond composites was verified using several processing parameters. Moreover, the influence of energy density on the microstructures and grain growth was also demonstrated theoretically and experimentally. The formation of different kinds of grain morphologies in the molten pool was ascribed to the temperature gradient and cooling rate, corresponding to the direction and size of grain growth. The generation of Ag-Cu nanowires at the grain boundaries was firstly found in the SLM technique, which was related to the pressure stress generated by the high cooling rate of SLM. This work hopefully opens new paths for the applications of high-performance Ag-Cu/diamond MMCs in various application fields. It also provides new possibilities for the controllable manufacturing of Ag nanowires during SLM.
选择性激光熔化（SLM）技术是制造具有可控结构的金属基复合材料（MMC）的一种可行替代方法；然而，由于增强材料产生的不可预测缺陷，其实施仍然具有挑战性。本研究主要通过热力学分析，研究了SLM过程中熔池尺度下Ag-Cu/金刚石复合材料的微观结构演变和晶粒生长。使用多个工艺参数验证了制造Ag-Cu/金刚石复合材料的可行性。此外，还从理论和实验上证明了能量密度对微观结构和晶粒生长的影响。熔池中不同种类晶粒形态的形成归因于温度梯度和冷却速率，这与晶粒生长的方向和尺寸相对应。在SLM技术中首次发现了晶界处Ag-Cu纳米线的生成，这与SLM高冷却速率产生的压应力有关。这项工作有望为高性能Ag-Cu/金刚石MMC在各种应用领域的应用开辟新途径。它还为SLM过程中Ag纳米线的可控制造提供了新的可能性。
