立方孔拓扑结构对多孔钛力学性能的影响

Effects of Topology of Square Pore on Mechanical Properties of Porous Titanium

采用钛网层叠烧结的方法制备出规则排列与错孔排列具备不同空间拓扑结构的多孔钛。采用扫描电镜观察多孔钛的微观结构,利用具有双差动位移传感器采集变形的Instron力学试验机测试样品压缩应力-应变曲线。通过压缩应力-应变曲线上弹性阶段中的曲线斜率求得其杨氏模量,以规定非比例压缩强度σ0.2为多孔材料的强度指标。经对比研究发现:2种不同的排列方式形成不同的空间拓扑结构。当方形孔错排时,弹性模量和屈服强度均呈现不同程度的下降,且弹性模量下降的幅度远远大于屈服强度下降的幅度。通过力学解析模型分析可知,挠度屈服和应力集中是力学性能下降的主要因素。

Porous titanium with two different topology structures was designed and fabricated by a titanium mesh-stacking-sintering method. The microstructure and mechanical properties of the porous titanium specimens were investigated by scanning electron microscope （SEM） and electrical universal testing machine, respectively. The Young＇s modulus and yield stress （σ0.2） were calculated from the stress-strain curves. The results show that the square pore distribution such as the staggered pore in the regular pore model can reduce the elastic modulus and yield stress as much as 74% and 10% at the same porosity, respectively. On the basic analysis from the analytical model, it is suggested that the bending and stress concentration are the main reasons of the elastic modulus and yield stress reduction.