Thermal Decomposition Characteristics Of TiH₂and Study On Foaming Process Of Aluminum Foam

Aluminum foam is a new structural and functional composite material with widely application prospect. Its excellent properties have drawn attention of many technologists. The preparation of aluminum foam by using melt foaming method is a simple preparation technique, and the preparation cost is low, therefore it is a promising to realise large-scale industrialized production. Aluminum foam has been applied in the aerospace, automotive, military and other fields. However, there are few public reports about thermal decomposition characteristics of foaming agent, the effect on the pore structure of aluminum foam and study on thermodynamic and dynamic of foaming process.Reducing the decomposition rate of TiH2can fully finish the foaming process, which can get foam sample of homogeneity pore structure. In order to analyse decomposition characteristics of blowing agent with different oxidation treatment condition, TiH2was treatmented in different temperature. The phase transformation of unoxided and oxided treatment TiH2was analyzed. The color of TiH2had different changed along with processing temperature, the paper researched the ability of thermal decomposition of TiH2, and TiH2of before and after the oxidation influence on foam sample.By obtaining the samples of aluminum foam in different foaming process, researched evolution of the bubble structure, changes of porosity, and the formation process of the free bubble layer, illustrated defects which appeared in the preparation of aluminum foam.From the theoretical point in this thesis, dynamic of foaming process of aluminum foam was analysed according to decomposing of foaming agent. This paper used for reference the foaming process of metallurgical slag, the dynamic equation of foaming process of aluminum foam was established, and then the influence rule of influencing factors on the evalution of foaming height was achieved in metal foam by means of numerical simulat’on, it offered the theory base to control the foaming process of metal foam. The free bubble layer was divided into three stages in this paper, and forming reason for each stage of the free bubble layer was analysed.In addition, the thermodynamic conditions of the different foaming stage of aluminum foam was detailed analyzed, obtained thermodynamic decomposition of blowing agent, thermodynamic condition on mode of bubble nucleation, bubble growth, movement and cracking, and the stability was analyzed theoretically in this paper.