Papers by Keyword: Silicon

Abstract: The oxidation of Ti-(43~52%)Al-2%W-(0~0.5%)Si alloys between 900 and 1050°C in air progressed via the outward diffusion of Ti ions to form the outer TiO₂ layer, and the inward transport of oxygen to form the inner (TiO₂+Al₂O₃) mixed layer, between which the intermediate Al₂O₃ barrier layer existed. Tungsten tended to diffuse inward to be incorporated below the intermediate Al₂O₃ layer, while Si outward to exist over the entire oxide layer. Both W and Si tended to be dissolved in the oxide layer, rather than forming independent oxides.

Abstract: This paper investigates the effect of bubble on the primary Si size in Al-18wt.%Si alloy. The primary Si size observed was varied with bubble size and bubbling time in bubble process. The effect of the holding temperature of the melt in bubbling process was also investigated. In water model, as the injecting bubble size decreases, the residual bubble size in the water decreases and the residual bubble conservation time in the water increases. Also in the experiment of Al melt, the primary Si size decreases, as the injecting bubble size decreases and as the bubble processing time increases. Pore was observed at the center of primary Si. This pore was observed at many Si phases. So, this experiment suggests that the bubble can be used as nucleation sites of primary Si.