Gamma-Titanium Intermetallic Alloy Produced by Selective Laser Melting Using Mechanically Alloyed and Plasma Spheroidized Powders

Abstract

Conventional manufacturing of titanium intermetallic alloys is associated with brittleness, hard machinability and, consequently, the high cost, which makes additive manufacturing a promising way of producing complex intermetallic parts. At the same time, γ-TiAl alloys exhibit good high temperature strength, fatigue, and oxidation resistance. In the present study the gamma-based alloy spherical powders were prepared by mechanical alloying from elemental powders followed by the plasma spheroidization process. Microstructure and phase composition of the produced powders were studied after different milling times in a planetary mill. The optimally milled powders were treated in the flow of thermal plasma to obtain powder particles with a high degree of sphericity. The produced spherical powders were used in Selective Laser Melting (SLM) process with high preheating temperatures to obtain crack-free intermetallic samples. The microstructure and phase composition of the SLM-ed TiAl-samples were investigated with regard to different process parameters.