粉末冶金工艺对4A11铝合金致密度的影响

Influence of powder metallurgy process on density of 4A11 aluminum alloy

采用粉末冶金法制备4A11铝合金,分析了压制力、烧结工艺以及挤压工艺对铝合金致密度的影响。研究表明:在一定压力范围内,铝合金的致密度随着压制力的增加而增加,当压制力到达一定值后,致密度趋于稳定。常规烧结过程不能使铝合金致密化,反而会使材料致密度有所下降。挤压使材料发生塑性变形,填补了材料中的孔洞,同时金属的流动划破了颗粒表面的氧化层,促进物质的扩散迁移,能够大幅度提高铝合金的致密度,其致密度最高达到97.8%。

4All aluminum alloy was prepared using powder-metallurgy method. The influences of forming pressure, sintering process and extruding on the density of aluminum alloy was analyzed. The research shows that the density of aluminum alloy is improved with the increase of pressing force in the certain pressure range, and the density tends to be stable when the pressing force arrives to a certain value. Conventional sintering process can＇t make aluminum alloy den- sification, on the contrary, which would lead to drop of the density. Plastic deformation occurred by squeezing, the holes in the material would be filled and at the same time, the oxide in the surface was destroyed by metal flow, which promoted diffusion and transference of material. By this way, the density of aluminum alloy was greatly improved, and the highest density was 97.8%.