Intermetallic reinforced Cr alloys for high-temperature use

A new family of Cr(Ta)-Cr2Ta intermetallic alloys based on Cr-(6-10)Ta (at%) is currently under development for structural use in oxidizing environments in the 1,000–1,300°C temperature range. These alloys show excellent strength and creep resistance and good oxidation resistance at high temperatures in air. Oxidation resistance comparable to commercial reactive element doped chromia-forming alloys and creep resistance comparable to single-crystal superalloys have been demonstrated. To date, only modest room-temperature fracture toughness (in the 11–12 MPa m½ range) has been achieved. Preliminary results of a promising approach to improve room-temperature fracture toughness via ductilization of Cr with MgO additions are discussed.