Microstructures and mechanical properties of V–V3Si eutectic composites

Abstract

Abstract V–V3Si eutectic alloys were directionally solidified in a high temperature optical floating zone furnace. Depending on the solidification conditions, several microstructures were observed, such as well-aligned broken lamellar, fibrous, or cellular microstructures. The interphase spacings increased with decreasing solidification rates in agreement with the Jackson-Hunt theory. The mechanical properties of the individual phases were investigated by nanoindentation. It was found that the modulus and nanoindentation hardness of V3Si are 214 and 13.8 GPa, respectively, and those of the V solid-solution are 165 and 3.4 GPa, respectively. The high-temperature strength was examined by tensile testing at elevated temperatures. Preliminary results show that the ductile-to-brittle transition temperature is about 800 °C for this composite, and its strength is significantly higher than conventional V solid-solution alloys.