Alloy and Powder Preparation of High Niobium Containing TiAl Based Alloys

Abstract

High Nb containing TiAl based alloys exhibit excellent corrosion resistance to molten zinc. They are expected to serve as the potential coating materials of corrosion resistance to molten zinc. Four TiAl-Nb alloys of good oxidation resistance and their powders were prepared by arc-melting and ball milling, respectively. The Microstructure, Hardness, Coefficient of thermal expansion, and grain size distribution of four as-cast TiAl-Nb alloys and their powders were investigated. In addition, EPMA analysis was employed to further examine the existential state of element Y in as-cast TiAl-Nb alloys. It was found that element Y existed in the form of YAl2 phase in the grain boundaries and triple junctions. Higher content of Al in TiAl-Nb alloy results in bigger Coefficient of thermal expansion. Lamellar microstructures and fine grains exert a positive influence on hardness. Powders prepared by ball milling displayed angular and irregular morphology.