Effect of Oxygen on the β-Grain Size of Cast Titanium

Grain refinement of titanium alloys during solidification is believed to have many benefits for processing and properties. Recent work has emphasized the importance of solute elements in grain refining cast titanium and it was demonstrated that the growth restriction factor is useful for predicting the grain refining effectiveness of solute elements in titanium. Despite oxygen being the major impurity element present in titanium alloys and having been previously identified as a theoretical growth restricting solute, its effect as a β-grain refiner is still unexplored. This paper investigates the effect of oxygen on the grain size in cast titanium alloys.