镁颗粒在烧结过程中的变化方式及其对泡沫铝制备的影响

 研究了粉末冶金法制备泡沫铝材料过程中,提高可发泡预制坯致密度的方法.分析了预制坯制备过程中影响致密度的因素以及致密化过程;研究了烧结处理过程中烧结温度、烧结时间对预制坯内部组织结构及其致密度的影响.着重分析了烧结处理对Mg颗粒以及泡沫铝孔径结构的影响.对于粉末粒度为75~150μm的原料粉末来说,将在400MPa的压制压力下制备的预制坯进行450℃烧结处理2h以上,可提高预制坯的致密度并能够增加基体的连续性,烧结后Mg颗粒尺寸为原来的2~3倍.实验结果表明：采用冷压的方式,在400MPa的压力下,对经过450℃烧结2h后的预制坯进行发泡,可以得到孔径均匀、孔隙率高的泡沫铝材料.

Variation pattern of Magnesium Particles in Sintering Process and Its Influence on the Manufacture of Aluminum Foam

The method for increasing the dense of foamable precursors in the process of manufacturing the aluminum foam by powder metallurgy route has been studied. The factors which have influence on the dense of foamable precursors in the process of preparation and the densification process have been discussed. The influence of sintering temperature and sintering time on the structure in the foamable precursors and the densification has also been discussed. The main discussion is focused on the influence of the sintering on the variations of magnesium particles and the quality of the aluminum foam manufactured by powder metallurgy. As for the matrix material which particles size is between 75~150μm, the foamable precursor which is sintered at 450℃ after cold compression would increase its density and the continuity of the matrix. The sintering time should not be less than two hours,therefore the size of the magnesium particle will be twice or even three times larger than that for the one that is not sintered. The results reveal that high quality aluminum foams could be obtained by uniaxial cold compaction under the pressure 400MPa with sintering at 450℃ for two hours. In this way, the quality of the aluminum foam could be better than the one without sintering.