粉体颗粒粒度对粉末冶金法制备泡沫铝材料的影响

Influences of Powder Particle Size on Preparation of Foamed Aluminum by Powder Compact Foaming Method

采用自制的Al-Si合金粉末为原料,将粒度为d<74μm,74μm<d<147μm,147μm<d<295μm的合金粉末分别与发泡剂(TiH2)混合,然后压制成金属坯,进行发泡实验.实验表明,随着粉末粒度的减小,TiH2的团聚现象减少,分布逐渐由"线-团"状变为"点"状.当合金粉末粒度为d<74μm时,TiH2呈"点"状,均匀分布在金属坯中.此时制得的泡沫铝材料,密度低、孔隙率高、泡孔分布均匀、泡体发育完全、泡壁较薄,是理想的泡沫铝材料.

With the powdered Al-Si alloy taken as raw material to prepare foam aluminum, the powdered alloy was classified into three powder particle sizes, i.e. , d 〈 74μm, 74μm〈 d 〈 147μm and 147μm 〈 d 〈 295μm, and each of them was blended with the foaming agent TiH2 separately. Then they were all pressed into blanks for foaming experiments. As shown in experimental results, the occurrences of TiH2 agglomeration decreases as the powder particle size decrease and, gradually, the agglomerated particles become linear even point-like ones in blank. When the powder particle size decreases to d 〈 74μm, all particles present point-like and are distributed uniformly in blank. In this way the high-quality foam aluminum can be obtained with low density, high porosity, thin pore walls, uniformly distributed pores and perfect foam growth.