Microstructure and mechanical properties of Ru–Al–Mo alloys

Alloys in the Ru–Al–Mo system were investigated and the microstructure and phase compositions of alloys produced by arc-melting and by a cold crucible Czochralski technique were examined. Two sets of alloys were examined. One consisted of eutectic microstructures between RuAl and a bcc (Mo, Ru) solid solution. The RuAl–(Mo, Ru) eutectic was found to have a room temperature yield stress of 1500 MPa. The microstructures from the other set of alloys consisted of RuAl and a hcp(Ru, Mo) solid solution. For these alloys, a change from eutectic to peritectic solidification occurs as the Mo concentration increases. The RuAl–hcp(Ru, Mo) eutectic microstructure was found to consist of RuAl fibers embedded in a (Ru, Mo) matrix. A near eutectic RuAl–(Ru, Mo) alloy was found to have a room temperature fracture toughness above 35 MPa√m.