Fracture Toughness at High Temperature of Tungsten-Rhenium Alloys

Fracture toughness tests of tungsten and tungsten-rhenium alloy were carried out at elevated temperatures. The effect of rhenium content on fracture toughness and the temperature dependence of fracture toughness were investigated. Fracture surface were observed in detail. Although the fracture toughnesses of three kinds of materials with rhenium of 0, 5 and 10wt% were almost identical at room temperature, the materials with higher rhenium content had the higher fracture toughness at elevated temperatures. The brittle-ductile transition similar to that of steels and the ductile-brittle transition at which recrystallization occurred, were observed for all three kinds of materials. With an increase of rhenium content, the brittle-ductile transition temperature decreased and the ductile-brittle transition temperature increased. A significant grain growth in the temperature range higher than the recrystallizing temperature, which was observed in the tungsten material without rhenium, was not found in the tungsten-rhenium alloy materials.