针对Ti-6Al-4V合金植入体存在的应力屏蔽问题,采用选区激光熔化技术成形了不同孔径和孔隙率的多孔Ti-6Al-4V合金结构,对样品的相对密度、成形精度、微观组织、压缩性能和弹性模量等进行表征。结果表明,原始打印态多孔Ti-6Al-4V合金结构的显微组织为细针状α'马氏体组织;不同相对密度的多孔Ti-6Al-4V合金结构,其相对密度从0.420升高到0.548时,弹性模量从15.1 GPa升高到25.7 GPa,抗压强度也从223 MPa升高到了352 MPa,且弹性模量、抗压强度随相对密度变化的关系满足Gibson-Ashby模型。此外,多孔Ti-6Al-4V合金压缩断裂发生在支杆连接处,断口与水平方向约成45°夹角,断裂方式为脆性断裂。

The porous Ti-6Al-4V alloy structures with different pore sizes and porosity are fabricated by selective laser melting aiming at the problem of stress shielding existing in the Ti-6Al-4V alloy implants. In addition, the relative densities, molding precision, microstructures, compression properties and elastic moduli of different porous samples are characterized. The results show that the microstructures of the as-built porous structures are composed of fine needle α' martensite phases. As for the porous Ti-6Al-4V alloy structures with deferent relative densities, when the relative density increases from 0.420 to 0.548, the elastic modulus increases from 15.1 GPa to 25.7 GPa, and the compressive strength increases from 223 MPa to 352 MPa. Moreover, the relationship of elastic modulus and compressive strength with relative density satisfies well with the Gibson-Ashby model. In addition, the compression fractures of porous Ti-6Al-4V alloys occur at the junction of struts. The angle between the fracture and the horizontal direction is about 45° and the fracture mode is a brittle one.