Cracking mechanism and a novel strategy to eliminate cracks in TiAl alloy additively manufactured by selective laser melting

Additive manufacturing of TiAl alloys by selective laser melting (SLM) remains a challenge due to serious cracking during the print process. In this work, the cracking mechanism of the SLM-fabricated Ti-48Al-2Cr-2Nb alloy is studied. Experimental results show that the cracks mainly occurred in the Nb-poor regions and near the interfaces between alpha(2) and B2 phases. A novel strategy to eliminate cracks is thus proposed: eliminating the Nb-poor regions and reducing the interface between different phases. It is found that by increasing Nb content, a nearly alpha(2) single-phase structure without heterogeneous interface formed along with the elimination of Nb-poor regions in the SLM-fabricated Ti-48Al-2Cr-8Nb alloy. The as-SLMed alloy is crack-free and of high strength, verifying the effectiveness of the proposed strategy. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the cracking mechanism of SLM-fabricated Ti-48Al-2Cr-2Nb alloy and proposes a novel strategy to eliminate cracks. Experimental results show that a crack-free and high strength alloy can be achieved by eliminating Nb-poor regions and reducing interfaces between different phases. The effectiveness of the proposed strategy is confirmed by the successful fabrication of a nearly alpha(2) single-phase structure in the SLM-fabricated Ti-48Al-2Cr-8Nb alloy.