使用选区激光熔化(SLM)技术制备了Ti6Al4V钛合金体心立方多孔结构, 分别研究了线能量密度和微杆直径对体心立方多孔结构成形方向(Z向)和非成形方向(X/Y向)压缩性能的影响。结果表明, 采用SLM技术成形的体心立方多孔结构存在明显的各向异性。随着线能量密度的下降, 体心立方多孔结构的抗压强度先增大后减小, 其各向异性程度在最优参数下达到最低。随着微杆直径的减小, 体心立方多孔结构的各向异性程度逐步降低; 当微杆直径降至0.4 mm时, 各向异性程度仅为3%左右。研究表明, 即使是各向同性的多孔结构, 采用SLM技术成形后, 也会表现出明显的各向异性; 这种各向异性与成形质量和层间界面有关, 通过调整工艺参数及修改模型特征尺寸可以在一定程度上减弱这种各向异性。

Body-centered-cubic porous structures of Ti6Al4V titanium alloys are prepared by the selective laser melting (SLM) technology. The effects of the linear laser energy density and the microrod diameter on the compressive property along the forming direction (Z axis) and non-forming direction (X/Y axis) of these body-centered-cubic porous structures are studied. The results show that the body-centered-cubic porous structures fabricated by the SLM technology exhibit an obvious anisotropy. With the decrease of the linear energy density, the compressive strength of these body-centered-cubic porous structures increases first and then decreases. The degree of anisotropy is the lowest under the optimal parameters. With the decrease of the microrod diameter, the degree of anisotropy gradually weakens and when the microrod diameter reaches 0.4 mm, the degree of anisotropy is only about 3%. The research indicates that, even an isotropic porous structure, after fabrication by SLM technology, shows an obvious anisotropy. Such an anisotropy is related to the forming quality and the interlayer boundary which can be weakened to a certain extent by adjusting process parameters and changing model characteristic dimensions.