Preparation Of Porous Aluminum Theoretical Basis

Porous metal is a new structural and functional composite material developed in recent years. Its excellent properties and applied prospects have drawn attention of technologists. But the basic theories producing porous metals in high temperature were not yet fully understood, especially the foaming mechanism, foaming thermo-dynamics study on nucleation , growth, movement and disappearance of gas pore were rarely researched.In this paper, micro-porous metals with 2-23 u m-pore diameter and 19.3-62.4% porosity were produced by the powder metallurgy. Through the experiments and SEM analysis, the effect of processing parameters on porous structure was studied. The results showed that with 1.5wt% TiH2, the porosity was the maximal and above 35/min average heating rate, the porosity clearly increased; And along with the increasing of compact pressure, preservation time and heating temperature, the porosity would be enhanced.The thermodynamic conditions of decomposition of the foaming agent TiH2, homogeneous and heterogeneous nucleation in high-temperature solid and liquid, growth and movement were achieved to demonstrate the trend of pore evolvement in this paper. Moreover, according to the characteristics of in-situ gas foaming, the equations of the height change of foaming samples with heating time were primarily established to study the behavior of foams and to guild the experiment processes.