Laser additive manufacturing of Zn porous scaffolds: Shielding gas flow, surface quality and densification

作     者：Peng Wen Yu Qin Yanzhe Chen Maximilian Voshage Lucas Jauer Reinhart Poprawe Johannes Henrich Schleifenbaum 

作者机构：The State Key Laboratory of Tribology Tsinghua University Key Laboratory for Advanced Materials Processing Technology MOE Tsinghua University Department of Mechanical Engineering Tsinghua University Digital Additive Production (DAP) RWTH Aachen University Fraunhofer Institute for Laser Technology (ILT) 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2019年第35卷第2期

页      面：368-376页

核心收录：

学科分类：0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：supported by National Natural Science Foundation of China (51875310) National Key R&D Program of China (2017YFB1103300) 

主　　题：Additive manufacturing Powder bed fusion Laser Porous scaffold Zn 

摘      要：Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and CT scanning. Massive Zn evaporation during laser melting largely influenced the formation quality during LPBF of Zn metal. The metal vapor in processing chamber was blown off and suctioned out efficiently by an optimized gas circulation system. Numerical analysis was used to design and testify the performance of gas flow. The surface of scaffolds was covered with numerous particles in different sizes. Processing pores occurred near the outline contour of struts. The average grain size in width was8.5m, and the hardness was 43.8 HV. Chemical plus electrochemical polishing obtained uniform and smooth surface without processing pores, but the diameter of struts reduced to 250 αm from the design value 300 m. The poor surface quality and processing pores were resulted by the splashing particles included spatters and powders due to the recoil force of evaporation, and the horizontal movement of liquid metal due to overheating and wetting. The insufficient melting at the outline contour combined with good wetting of Zn liquid metal further increased the surface roughness and processing pores.