多孔件TC4选区激光熔化成形及力学性能分析

Analysis on the formation and mechanical properties of the TC4 porous structures by selective laser melting

摘要:

采用选区激光熔化成形技术制备了两种钛合金体心立方多孔结构(BCC和BCC-Z)制件,验证了其成形复杂孔制件的可行性；进行了静态压缩试验,结果表明制件沿近45°方向断裂；压缩试验应力应变曲线表明多孔件使材料抗拉强度大大减小,且随着边径比和孔隙率的增大,峰值应力减小。同时,在边径比和孔隙率相差不大的情况下,BCC-Z结构承受载荷的能力明显高于BCC结构；通过有限元模拟分析了BCC制件在压缩过程中的应力分布情况,针对单元体节点处的应力集中现象,提出了节点加固方法。同时预测了多孔制件的弹性模量和屈服强度,模拟与试验结果基本吻合。

Abstract:

Two kinds of BCC and BCC-Z Titanium alloy porous structures were manufactured by selective laser melting, and its feasibility of forming complex porous structures was verified. Then, static compression tests were carried out and the results show that the products always fracture around 45 °. The stress strain curve shows that the tensile strength of the porous structures is greatly reduced, and the peak stress is decreased with the increase of the ratio of length diameter and porosity. In addition, in the case of similar ratios of length diameter and porosity, the ability to bear loads of BCC-Z is significantly higher than that of BCC. Finally, the stress distribution of BCC parts in the process of compression was analyzed by finite element simulation. In view of the stress concentration at the nodes of the unit, the method of node reinforcement was put forward. And the elastic modulus and the yield strength of the porous products are predicted, which fits the experiment results.