Abstract
The wettability of SiC fibres to molten aluminum was investigated by a dip-coverage method, and was compared with previous results of that of SiC block. At higher temperatures around 1273K, the coverage ratio of SiC fibres by pure aluminum is less than that of SiC block since the rate constant of overall reaction k0 is distinctiy lower and the incubation time τ is longer. However, alloying of Ti, Hf and V, increases k0 and shortens τ for SiC fibres. In this case, those values are as much as the level of SiC block. These adverse results can be explained by considering Wenzel's equation which expresses the effect of roughness of solid/liquid interface on the wettability. At a lower temperature of 1023K, addition of Ca or Ca with Mg improves the wettability between SiC block and liquid aluminum. When SiC short fibres were incorporated into Al-Mg-Ca alloy at 1073K, the distribuition of SiC short fibres was more uniform than that in Al-Mg alloy. Hence, the simultaneous addition of Ca and Mg obviously contributes to the good wettability of SiC fibres to liquid aluminum, too.
