稀土La含量对多孔Ti-Mo合金孔隙形貌及性能的影响

Effect of rare earth La content on pore morphology and properties of porous Ti-Mo alloy

以稀土La为增强剂、碳酸氢铵为造孔剂,采用粉末冶金法在1 200℃真空条件下烧结制备多孔Ti-Mo合金,研究不同稀土La含量对其物相成分、孔隙形貌、孔隙率、抗压强度及耐腐蚀性能的影响。结果表明:多孔Ti-Mo合金具有α+β双相组织,孔径为(50~250)μm;随着稀土La含量的增加,材料孔壁表面松散的粉末颗粒逐渐减小,颗粒间的距离缩短,当La的质量分数为1.0%,材料孔隙结构均匀、孔壁光滑,孔隙率最大。添加一定量稀土La,可以减小材料的径向收缩率,提高抗压强度和耐腐蚀性,当La的质量分数为1.2%时径向收缩率最小,为5.6%;La的质量分数为0.2%时抗压强度最大,最大值为84 MPa;La含量越高,材料的耐腐蚀性越强。

With rare earth La as strengthening agent and ammonium bicarbonate as pore-forming agent,the porous Ti-Mo alloy was prepared by using the powder metallurgy method under the condition of 1 200℃vaccum sintering.The effects of La content on phase composition,pore morphology,porosity,compressive strength and corrosion resistance were studied.The results show that the porous Ti-Mo alloy containsα+βbiphase structure with a pore diameter between 50μm and 250μm.With the increase of rare earth La content,the loose powder particles on the surface of the pore wall of the material gradually decrease,and the distance between the particles is shortened.With 1.0%mass fraction of La,the pore structure of the material is uniform,the pore wall is smooth,and the porosity is the largest.Introducing a certain amount of rare earth La into the porous Ti-Mo alloy,the radial shrinkage of the material reduces,and the compressive strength and corrosion resistance effectively improve.With 1.2%mass fraction of La,the radial shrinkage is the smallest,and the minimum value is 5.6%.With 0.2%mass fraction of La,the compressive strength is the largest,and the maximum value is 84 MPa.The higher La content is,the higher the corrosion resistance of the material possesses.