Study On The Preparation And Characteristics Of Organizations Of Al-Si Alloy Foam Which Viscosity Increased By SiC Particles

The purpose of this study was to develop the process route and its various elements of reasonable parameters that aluminum foam which viscosity increased by SiC particles can be prepared by melt casting method. And get new aluminum foam with uniform porosity, suitable pore size.This paper compares the different process routes and theory between traditional preparation of aluminum foam, which uses aluminum or alloy of aluminum and this preparation that uses Sic particulate to increase the viscosity of the melt, through comparisons ,we can see that the process route of this study can save the process of Increasing viscosity and can be operated easily. Then the decomposition thermodynamics and kinetics of the blowing agent are analyzed more detailed.TiH2 begins to decompose in the 350℃to 420℃, a large number of hydrogen release in more than 420℃, and the release finishes till the melting point of titanium (1668℃). The hydrogen release only 60-75% under 600-700℃and the remaining gases continue to be steady with the metal-binding until the foam stop. Then the foam theory of the melt casting method is analyzed, the bubble formation, growth and merger are also analyzed. This study has a profound theoretical basis.According to the theoretical analysis and previous experience, the pretreatment process for the blowing agent is to be heated in 400℃for 24 hours, and then 500℃for one hour. The stirring speed when blowing agent is added is 1000r/min; stirring time is about one minute. In order to determine a reasonable temperature for adding powder, four technologies were developed. They are technologies that the powder is added in the temperature of 610℃, 640℃, 660℃, and 670℃. By comparison, in the technology that the powder is added in the temperature of 640℃, we can get more ideal foam. Then the reason why Not foam layer and incomplete foam layer were formed.The prepared foam is sawn into round pieces along radial, Analysis the average pore size and porosity of each sample respectively. Then each of the samples was divided into three regions, the average pore size and porosity of every region was analyzed too. According to the measured data of every region, the curves about the average pore size and porosity of axial and radial directions were made. By the various curves, we can see that the average pore diameter and the porosity of each sample increased along the radial direction; the average pore diameter and the porosity in the axial direction decreases with the height increases.The results show that: a new type of foam can be prepared by using TiH2 as foaming agent and ZL104 alloy and aluminum matrix composite materials as foam matrix. The process is simple, do not require special processing equipment, and do not require specialized process of increasing viscosity. It has good prospects for development.The study also show that: the average diameter and porosity of the foam ingot is gradually increasing from the centre to the edge of the pattern. In addition, with the increase of the high degree, the average diameter and porosity of the foam ingot is gradually decreasing. The decreasing percentage of the average diameter and porosity of the center area are 5.7%,42.4% respectively, and that of the area 20mm far from the center are 28.2%,36.5%, that of the area 40mm far from the center are 26.3%,33.1%,...