生物医用多孔Ti-6Mo合金选择性激光烧结的结构特征和力学行为

Structural characteristics and mechanical behavior of selective laser sintered porous Ti-6Mo alloy for biomedical applications

摘要:

采用选择性激光烧结金属元素粉末Ti、Mo和粘结剂的混合粉末,制备了多孔Ti-6Mo合金,并研究了其结构特征和力学性能。结果表明,多孔Ti-6Mo合金的孔隙结构与烧结工艺有关,随着烧结温度从1000 ℃升高到1200 ℃,孔隙由三维连通孔变为相互孤立孔,孔隙率从58%下降到24%,孔径从112 μm减小到43 μm；多孔Ti-6Mo合金在室温为片层组织,均由大量α相和少数β相构成,并伴有微量α-Ti析出物；压缩应力-应变曲线表现为弹性变形、塑性屈服和断裂区三阶段,随着孔隙率降低,弹性模量和屈服强度分别在2.07~11.9 GPa和31.4~152.8 MPa增大,且相对弹性模量和相对屈服强度和相对密度之间遵循幂律关系。多孔Ti-6Mo合金的孔隙特征和力学性能均可满足自然骨要求,是一种可行的医用材料。

Abstract:

Porous Ti-6Mo alloy was prepared from mixed powders of Ti, Mo and binder by selective laser sintering, and the structural characteristics and mechanical properties were investigated. The results show that the pore features are connected with the sintering process. As the sintering temperature rises from 1000 to 1200 ℃, the pore morphology changes gradually from interconnected to isolated pores, and the porosity level reduces from 58% to 24%, as well as the pore size from 112 to 43 μm. The porous alloy exhibits a laminar microstructure composed of dominant α and minor β phases together with trace amounts of α-Ti precipitations at room temperature. The compressive stress-strain curves consist of elastic deformation, plastic yield and fracture stage. The elastic modulus and yield strength increase respectively in the ranges 2.07-11.9 GPa and 31.4-152.8 MPa with the decrease in porosity, meanwhile the relationship between the relative mechanical properties and relative density is found to obey a power law relation. Porous Ti-6Mo alloy may be a feasible biomaterial based on the fact that both porous structure and mechanical properties can achieve the requirement of natural bones.