Effects of addition of rare earth element Gd on the lamellar grain sizes of a binary Ti-44Al alloy

Abstract

A study was conducted to clarify the effects of adding the rare earth (RE) element Gd on the refinement of lamellar grains in a binary Ti-44Al alloy. The macrostructures were observed using a low magnification microscope, while the microstructures were examined using optical microscopy. RE addition significantly reduced the lamellar grain sizes in the alloys. The grains were refined to approx. 400 μm with an addition of 0.5 at% Gd. Hot-pressing by approx. 15% in height reduction only led to marginal grain refining in the binary alloy whereas the deformation resulted in dramatic reduction in grain sizes to approx. 140 μm in the Gd containing alloy.