Fatigue Strength of Aluminum Matrix Composite Reinforced with Aluminum Borate Whisker.

Recently, various kinds of oxide whisker have been developed which are much cheaper than SiC or SiA4 whiskers.These oxide whiskers may be available for fillers which reinforce metal matrix composites.We have already studied on the microstructural change at interface and tensile properties of oxide whiskers reinforced aluminum and aluminum alloy matrices composites.The results were that aluminum borate whisker reinforced composite revealed the most superior specific strength and the most stable microstructure of all.The aim of this study was to make clear the fatigue behavior of the composite comparing with SiC whisker reinforced one.Fatigue limits were increased with volume fraction like that of SiC whisker reinforced one, however, the dependence of whisker volume fraction on fatigue strength was weaker than that for SiC whisker reinforced one.This difference was considered to be due to smaller aspect ratio of aluminum borate whisker which decreased more than that of SiC whisker with increasing whisker volume fraction.