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 environmen ts in the 1,000-1,300 degrees C temperature range. These alloys show excell ent strength and creep resistance and good oxidation resistance at high tem peratures in air. Oxidation resistance comparable to commercial reactive el ement doped chromia-forming alloys and creep resistance comparable to singl e-crystal superalloys have been demonstrated. To date, only modest room-tem perature fracture toughness (in the 11-12 MPa m(1/2) range) has been achiev ed. Preliminary results of a promising approach to improve room-temperature fracture toughness via ductilization of Cr with MgO additions are discusse d.