增材制造Ti-6Al-4V点阵材料的研究进展

Research Progress on Additive manufactured Ti-6Al-4V Lattice materials

摘要:

增材制造技术成形Ti-6Al-4V点阵材料具有高强度、低密度、生物相容性好的性能特点,在航空航天、生物医疗、海洋等领域具有极大应用潜力。本文概述了近年来增材制造Ti-6Al-4V点阵材料的研究进展,重点对选区激光熔化(SLM)和电子束选区熔化(SEBM)技术成形点阵材料的力学性能、失效行为、微观组织进行分析与总结。研究发现,SLM和SEBM技术均可获得保留原始结构特征的点阵材料,且增材制造骨骼型Diamond 极小曲面Ti-6Al-4V点阵材料抗压强度可达到411.71 MPa,屈服强度达到317.48 MPa,强度可与镁合金相媲美；点阵材料失效行为主要有45°剪切断裂以及水平断裂,剪切断裂型点阵材料强度较高,在承载方面具有独特优势,而呈水平方向断裂的点阵材料多为梯度型点阵材料,其应力应变曲线波动范围较小,在能量吸收能力方面表现出明显的优势；热处理可有效消除增材制造过程中带来的残余应力、降低粗糙度、转变亚稳、针状α"马氏体为α+β相,进而增加点阵材料的塑性,且不降低甚至提高部分Ti-6Al-4V点阵材料的强度。最后,对增材制造Ti-6Al-4V点阵材料的现存弊端以及未来发展趋势进行了展望。

Abstract:

High-strength, Low density periodic Ti-6Al-4V lattice materials built with additive manufacturing provide relatively widespread applications for aerospace, biomedicine, marine and other fields. In this paper, the reported compressive properties, failure modes, microstructure and the heat treatment of Selective laser melting (SLM) and Selective electron beam melting (SEBM) additive manufatured Ti-6Al-4V lattice materials are reviewed. According to statistics, the continuous and integrated lattice materials can be manufatured via SLM and SEBM. And more importantly, the compressive strength and yield strength of skeleton-based Diamond TPMS lattice materials can reach to 411.71 MPa and 317.48 MPa respectively, which are comparable to those of magnesium alloys. It is also be found that the main failure modes of Ti-6Al-4V lattice materials are 45° shearing fracture and horizontally fracture. Shearing fractured lattice materials have unique advantages in load-bearing capacity, while horizontally fractured lattice materials with smaller fluctuation in stress-strain curves, showing dominant superiority in energy absorption capacity. Heat treatment is an effective method to eliminate the residual stress, reduce the roughness and transform acicular α "martensite to α+β phase caused by additive manufacturing, and then increase the ductility of lattice materials without reducing or even increasing the strength of Ti-6Al-4V lattice materials. Finally, the existing disadvantages and future development trend of additive Ti-6Al-4V lattice materials are prospected.