TC4钛合金负泊松比人工骨微结构的力学性能匹配研究

Study on mechanical property matching of TC4 titanium alloy negative Poisson

摘要:

金属人工骨植入体的设计以正泊松比多孔结构为主，而少有针对超材料负泊松比多孔结构的设计研究。本文设计不同变形机理、不同孔隙率下的负泊松比多孔骨结构材料，借助选区激光融化成型技术制备医用Ti6Al4V负泊松比多孔植入物样件，进行微观材料表征和可制造性评测，以及通过压缩试验揭示强度、弹性模量等力学性能与胞元结构类型、结构参数间的影响规律，评测不同结构与人骨力学性能的匹配程度。结果表明：各结构都具有较高的可制造性，成型质量与结构特征和孔隙率相关；负泊松比结构力学性能高度依赖于结构设计及孔隙率；所设计的负泊松比结构通过改变支柱直径能够将实体金属弹性模量降低至与人体骨骼相近的范围内，并有望通过调整结构参数进一步实现植入体力学性能的广跨度调控。

Abstract:

For the design of pore structure of titanium alloy implants, most of the current researches were on positive Poisson"s ratio pore structures, while few of them were concerned with the design of negative Poisson "s ratio pore structures. Some samples of titanium alloy negative Poisson "s ratio pore structure implants with different deformation mechanisms and porosities were fabricated by selective laser melting(SLM), and microscopic material characterization was performed, and manufacturability evaluation was completed. Through the test of mechanical properties, the related mechanical data were obtained, which reveal the influence of mechanical properties such as strength and elastic modulus on cellular structure types and structural parameters through compression tests, and evaluates the matching degree of different structures with mechanical properties of human bone. The results show that: each structure has high manufacturability, and the forming quality is related to the structural characteristics and porosity; The mechanical performance of negative Poisson"s ratio structure highly depends on the structure design and porosity; The designed negative Poisson"s ratio structure can reduce the elastic modulus of solid metal to a range close to that of human bones by changing the diameter of the struts, which is expected to further achieve a wide-span regulation of the mechanical properties of the implant by adjusting the structural parameters.