Microstructure of rapidly solidified Ti–Al–V and Ti–Al–Si–V alloys

The microstructure and oxidation resistance of melt-spun Ti–25Al–(0–7.5)Si at.% ribbons containing up to 15 at.% V were studied. V additions do not change the course of the eutectic reaction in the Ti–Al–Si alloys and lead to two phase B2–(Ti, V)(Al, Si) and ζ-(Ti, V)5(Si, Al)3 eutectic structures. TEM observations of hypoeutectic ingots and ribbons showed large antiphase domains (APDs) in the primary B2 dendrites. Rapid solidification by chill block melt spinning resulted in a shift in the coupled zone for the Ti–Al–Si–V eutectic alloys towards the ζ phase. Addition of 15 at.% V significantly decreases the oxidation resistance of Ti3Al–Si alloys at high temperatures.