純アルミニウム中におけるα–AlFeSi晶出相の球状化機構

抄録

It is observed that α–AlFeSi nodules during the solidification in pure aluminum. Assuming that this phase particles form in hydrogen bubbles during the solidification, the following experiments were done: 1) the observation of structures of α–AlFeSi nodules, 2) the effect of hydrogen bubbles on the formation of α–AlFeSi nodules. As a result, it became clear that the morphology of α–AlFeSi nodules, which forms during solidification is a spherical shape with a hollow shell. This structure indicates that α–AlFeSi particles nucleate on the inner wall of the hydrogen bubbles which evolve during solidification. Furthermore, the size and density of α–AlFeSi nodules changed with the cooling rate of solidification and their variations agreed with those of the hydrogen bubbles. It is considered that the above results support the hypothesis, that α–AlFeSi particles nucleate on the innner wall of hydrogen bubbles.