粉末冶金法制备泡沫铝时增粘过程的基础研究

在研究粉末冶金法制备泡沫铝过程中,在铝硅合金粉末中加钙增粘,提高了泡沫铝熔体的稳定性与孔结构的均匀性.论述了加钙增粘的机理及不同加钙量对泡沫铝孔隙率、孔结构的影响.经对发泡过程的动态观测,证明熔体粘度对泡沫体稳定性的影响是至关重要的.试验结果表明:在采取严格的气体保护措施条件下,加钙量在2%～2.5%时,可获得较低密度且孔径均匀的泡沫铝材料.

Study on the Process of Increasing Viscosity for Producing Foam Aluminum by the Powder Metallurgy Method

Some of the factors which affect the foaming in a foamed aluminum casting process and microstructural evolution of metal foams have been investigated by applying the powder compact process in many literatures. But few studies on the effect of viscosity of the molten and on the mechanisms stabili(zing) the pore formation have been undertaken. In this paper, foamed aluminum was preparation by powder metallurgy, the viscosity of the liquid metal was adjusted by Ca-addition into the metal, resulting in improvement of stabilization of bubble and uniformity of pore microstructure. The mechanisms stabilizing of the pore formation have been is investigated, and the effect of Ca addition on porosity and pore microstructure is studied. Moreover, it has been proved that the effect of viscosity on the stabilizing of the molten is more important than oxide layer by means of dynamic observation on foaming course.