梯度多孔Ti-15Mo合金材料的制备与压缩变形行为

Fabrication and Compressive Deformation Behavior of Gradient Porous Ti-15Mo Alloy Material

使用激光选区熔化技术分别制备具有支杆晶胞(BCC、Kelvin晶胞)和三重周期最小曲面(TPMS)晶胞(Primitive、Gyroid、Diamond晶胞)的多孔Ti-15Mo合金试样,孔隙率分别为均匀分布(均匀试样),沿成形方向递增(垂直梯度试样)和垂直于成形方向递增(横向梯度试样),研究了其压缩变形行为。结果表明:多孔试样的倾斜支杆或曲面会黏结更多粉末,成形质量相对较差;垂直梯度试样的变形机制为由顶部到底部的逐层变形,横向梯度试样的变形机制为先整体均匀变形,随后局部发生显著变形,并且变形向均匀变形区扩展;TPMS晶胞试样的压缩性能和能量吸收能力整体上高于支杆晶胞试样;Diamond晶胞试样的综合性能最优,其横向梯度试样的弹性模量、屈服强度、平台应力、累积能量吸收值分别为4.088 GPa、134.5 MPa、175.4 MPa、117.92 MJ·m^(-3),垂直梯度试样的分别为3.761 GPa、104.8 MPa、165.2 MPa、92.19 MJ·m^(-3)。

Porous Ti-15Mo alloy specimens with support cells(BCC,Kelvin cells) and triple periodic minimum surface(TPMS) cells(Primitive,Gyroid,Diamond cells) were prepared by laser selective melting.The porosity was evenly distributed(uniform specimen),increasing along the forming direction(vertical gradient specimen),increasing perpendicular to the forming direction(lateral gradient specimen).The compressive deformation behavior of the alloy was studied.The results show that the inclined support or surface of the porous sample would bond more powder,and the forming quality was relatively poor.The deformation mechanism of vertical gradient specimens was layer by layer from the top to the bottom,and the deformation mechanism of lateral gradient specimens was the whole uniform deformation first,and then the local significant deformation occurred and extended to the uniform deformation region.The compressive properties and energy absorption capacity of TPMS cell specimens were higher than those of the support cell specimens.The Diamond cell specimen had the best comprehensive properties.The elastic modulus,yield strength,platform stress and cumulative energy absorption values of lateral gradient specimen were respectively 4.088 GPa,134.5 MPa,175.4 MPa,117.92 MJ·m~(-3),and those of vertical gradient specimen were respectively 3.761 GPa,104.8 MPa,165.2 MPa,92.19 MJ·m~(-3).