造孔剂大小对泡沫钛孔隙结构的影响

Effects of Spacer Size on Pore Structure of Titanium Foams

采用3种颗粒大小的尿素作为造孔剂,在造孔剂含量相等的条件下进行了泡沫钛的制备,考察了造孔剂大小对泡沫钛结构和力学性能的影响,讨论了造孔剂大小对烧结泡沫孔隙率的影响。添加粒度更小的造孔剂颗粒,有利于提高生压坯的致密度。小颗粒造孔剂制备的泡沫钛的孔径更小,孔棱的结构和厚度分别更加致密和均匀。改变造孔剂的颗粒大小,泡沫钛应力-应变曲线的弹性部分变化不大,坍塌平台有明显的变化。结果表明,泡沫钛的相对密度和杨氏模量随着造孔剂粒径的减小而微弱的增大,而抗压强度则明显的增大。分析表明,泡沫钛的宏观大孔在烧结过程的体积收缩量随着造孔剂粒径的减小而减小。

Titanium foams were prepared via powder metallurgy using three different sizes of carbamide particles as spacer in the case of identical spacer content. The effects of spacer size on microstructure and mechanical properties such as Young＇s modulus and compressive strength were investigated. The effects of spacer size on porosity of sintered foams were discussed as well. Addition of finer spacer particles would enhance the density of green compacts. The finer space holder results in smaller macropores of foams, of which the structure and thickness of cell-edges tend to be denser and more uniform, respectively. The elastic portion of compressive stress-strain curves changes slightly when changing spacer size, while a distinct change occurs in the collapse plateau. The results indicate that the relative density and Young＇s modulus of titanium foams tend to slightly increase as decreasing spacer size, while the compressive strength apparently increases. The volume shrinkage content of macropores in sintering decreases with the spacer size decreasing.