Microstructure and mechanical properties of TiAl-based alloy produced by selective laser melting

Abstract

Additive Manufacturing (AM) is an attractive way of producing parts of intermetallic titanium alloys. However, high brittleness of these alloys makes it challenging to produce crack-free intermetallic parts by AM. One way to overcome this problem is to use high-temperature powder-bed preheating. In this paper, Ti-48Al-2Cr-2Nb alloy was obtained by selective laser melting process with high-temperature preheating of 800-900 ºC. Crack-free specimens with a relative density of 99.9% were fabricated using an optimized process parameter set. Microstructure and phase composition were studied using scanning electron microscopy and X-Ray diffraction to reveal a fine microstructure consisting of lamellar α2/γ colonies, equiaxed γ grains, and retained β phase. Compressive tests and microhardness measurements showed that the produced alloy exhibited superior properties compared to the conventionally obtained TiAl-alloy. reports the results of the investigation of L-PBF process using Ti-48Al-2Cr-2Nb alloy powder with an inductive high-temperature platform preheating. The effects of L-PBF process parameters and preheating temperature on fabricated TiAl-alloy microstructure and mechanical properties are investigated.