Phase Evolution in Laser Rapid Forming of Compositionally Graded Ti-Ni Alloys

A graded binary titanium-nickel alloy with a compositional gradient, from elemental Ti to Ti-23.2 at. % Ni, has been successfully deposited using laser rapid forming. A metallurgical study of the phase evolution along the compositional gradient showed that a series of phase evolutions alpha ->alpha+beta ->alpha+beta+Ti(2)Ni ->beta/beta 2+Ti(2)Ni have occurred. Phase formation and microstructure evolution along the compositional gradient was analyzed by Scheil-Gulliver and eutectic growth models. In particular the morphology of the beta/beta 2 + Ti(2)Ni anomalous and coupled eutectic is discussed in detail. [DOI: 10.1115/1.3184028],