An innovative way to fabricate γ -TiAl blades and their failure mechanisms under thermal shock

The near-net-shape gamma -TiAl blades were built by selective electron beam melting. As-fabricated material exhibits a good combination of microstructure homogeneity, tensile properties and thermal shock resistance at 700 degrees C owing to the optimised process parameters. The consistent and reliable approach to achieve this manufacturing success is elaborated. By performing thermal shock experiments at 900 degrees C, a new cracking mechanism has been identified. Through the post-mortem examinations, we reveal that such failure mode is most likely associated with the layer-by-layer strategy. Oxidation in conjunction with the surface topology is the underlying mechanism. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Automated summary

In this study, near-net-shape gamma-TiAl blades were built using selective electron beam melting. The material exhibited excellent properties at 700 degrees C due to optimized process parameters. A new cracking mechanism was identified through thermal shock experiments at 900 degrees C, likely associated with layer-by-layer strategy and oxidation combined with surface topology.