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 ...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.展开更多
钛及其合金的粉末床熔融式(PBF)增材制造技术因具有定制制造、成本节约和时间优化等优势,在航空以及生物医学领域备受关注。但在PBF制造钛合金时,多种因素如热导率低、热积累、氧化敏感性及快速冷却引起的热应力共同导致成形件缺陷、组...钛及其合金的粉末床熔融式(PBF)增材制造技术因具有定制制造、成本节约和时间优化等优势,在航空以及生物医学领域备受关注。但在PBF制造钛合金时,多种因素如热导率低、热积累、氧化敏感性及快速冷却引起的热应力共同导致成形件缺陷、组织差异、性能不稳定与质量参差不齐等问题。因此,本文通过调研PBF技术中的激光粉末床熔融(Laser powder bed fusion,L-PBF)和电子束粉末床熔融(Electron beam powder bed fusion,EB-PBF)技术原理,讨论PBF增材制造钛合金微观组织特征、力学性能、耐腐蚀性能、耐磨损性能与生物相容性的特点;同时,聚焦成形过程中的缺陷形成机理及影响,提出缺陷消除方法;最后,展望两种技术的未来发展方向,为促进创新钛合金增材制造提供新的研究思路。展开更多
基金supported by National Natural Science Foundation of China (51875310)National Key R&D Program of China (2017YFB1103300)
文摘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.
文摘钛及其合金的粉末床熔融式(PBF)增材制造技术因具有定制制造、成本节约和时间优化等优势,在航空以及生物医学领域备受关注。但在PBF制造钛合金时,多种因素如热导率低、热积累、氧化敏感性及快速冷却引起的热应力共同导致成形件缺陷、组织差异、性能不稳定与质量参差不齐等问题。因此,本文通过调研PBF技术中的激光粉末床熔融(Laser powder bed fusion,L-PBF)和电子束粉末床熔融(Electron beam powder bed fusion,EB-PBF)技术原理,讨论PBF增材制造钛合金微观组织特征、力学性能、耐腐蚀性能、耐磨损性能与生物相容性的特点;同时,聚焦成形过程中的缺陷形成机理及影响,提出缺陷消除方法;最后,展望两种技术的未来发展方向,为促进创新钛合金增材制造提供新的研究思路。
