Cracking mechanism and a novel strategy to eliminate cracks in TiAl alloy additively manufactured by selective laser melting. (November 2021)

• Record Type: Journal Article
• Authors: Wang, M.S.; Liu, E.W.; Du, Y.L.; Liu, T.T.; Liao, W.H.
• Is Part Of: Scripta materialia. Number 204(2021)
• Publication Date: 2021-11
• Subjects: Selective laser melting -- Titanium aluminides -- Solidification microstructure -- Cracking mechanism; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2021.114151
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: 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 α2 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 α2 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. Graphical abstract: Image, graphical abstract