As metal fiber (Fe-Cr-Si fiber) fabricated by melt extraction method (NHK spring Co., Ltd.) has superior high temperature strength, and magnesium alloys are lightweight, Fe-Cr-Si fiber reinforced magnesium alloy composites are expected to be lightweight as well as have superior high temperature strength. However, to date, there have bean no reports on the fabrication of Fe-Cr-Si reinforced magnesium alloy composites, and mechanical properties of these composites are not known. In this study, tensile strength of Fe-Cr-Si reinforced magnesium alloy composites was measured from room temperature to 573 K. Moreover, the relationship between experimental and theoretical strength was examined. At all tested temperatures, the composites had higher strength than matrix metal. Compared to JIS-AC8A aluminum alloy (Al-12Si-Cu-Ni-Mg alloy), the composites showed superior high temperature strength at more than 523 K. By means of Baxter's equation which takes into account interfacial bonding strength, the tensile strength of the composites at room temperature was approximately close to the theoretical strength of weak bonding models. At elevated temperatures, the experimental strength approached the theoretical strength of rigid bonding models. This suggests that the interfacial bonding strength increased at elevated temperatures.
