泡沫钛制备及力学性能评价研究

利用占位体烧结法在不同的占位体粒径、体积分数以及不同的烧结温度、时间条件下制备出泡沫钛。采用光学金相、扫描电镜等对泡沫钛的孔隙结构进行分析;通过室温压缩实验对泡沫钛的力学性能进行评价。结果表明,泡沫钛孔隙横截面呈圆形,纵截面呈椭圆形,其孔隙率与占位体体积分数的差值随占位体粒径、体积分数的增加、烧结温度的升高、时间的延长呈升高的变化趋势。同时,烧结温度越高,所制备的泡沫钛孔壁越致密。与传统的泡沫材料不同,泡沫钛应力-应变关系曲线并没有出现明显的应力平台,抗压缩强度和弹性模量随孔隙率的增加呈下降的变化趋势,当孔隙率为67.6%时,抗压缩强度和弹性模量分别达到14.4 MPa和1.17 GPa。抗压缩强度随孔径的增大呈先升高再降低的变化趋势,而弹性模量随孔径的增加基本不变,当孔径达到1.15～1.53 mm时,其抗压缩强度和弹性模量分别达到48.9 MPa和1.72 GPa。

Study on Preparation of Titanium Foam and Mechanical Properties

Titanium foam was prepared by space holder sintering process under different particle diameter, volume ratio and sintering temperature and time. The pore structure of titanium foam was analyzed by optical metallography and scanning electron microscope. The mechanical properties of titanium foam were evaluated by compression test at room temperature. The results show that the pore of titanium foam is round on the cross-section and is elliptical on the longitudinal section. The difference between the porosity of titanium foam and the volume ratio of space holder increases with the increase of the particle diameter, volume ratio, sintering temperature and time. At the same time, the higher the sintering temperature, the denser the pore wall of titanium foam is. Unlike the traditional foam materials, there is no obvious stress platform in the relationship between the stress and strain of titanium foam. The compressive strength and elastic modulus decrease with the increase of porosity. When the porosity is 67.6%, the compressive strength and elastic modulus reach 14.4MPa and 1.17GPa respectively. The compressive strength increases first and then decreases with the increase of pore diameter, while the elastic modulus remains unchanged. When the pore diameter reaches 1.15-1.53 mm, the compressive strength and elastic modulus reach 48.9 MPa and 1.72 GPa respectively.