Effect of building direction on the microstructure and tensile properties of Ti-48Al-2Cr-2Nb alloy additively manufactured by electron beam melting

By Mitsuharu Todai, Takayoshi Nakano, Tianqi Liu, H. Yasuda, K. Hagihara, Ken Cho, M. Ueda, M. Takeyama. 2017

219 citations recorded by the source corpus.

Abstract This paper clarified a novel strategy to improve the tensile properties of the Ti-48Al-2Cr-2Nb alloys fabricated by electron beam melting (EBM), via the finding of the development of unique layered microstructure composed of duplex-like fine grains layers and coarser γ grains layers. It was clarified that the mechanical properties of the alloy fabricated by EBM can be controlled by varying an angle θ between EBM-building directions and stress loading direction. At room temperature, the yield strength exhibits high values more than 550 MPa at all the loading orientations investigated ( θ  = 0, 45 and 90°). In addition, the elongation at θ  = 45° was surprisingly larger than 2%, owing to the development of this unique layered microstructure. The anisotropy of the yield strength decreased with increasing temperature. All the examined alloys exhibited a brittle-ductile transition temperature of approximately 750 °C and the yield strength and tensile elongation at 800 °C were over 350 MPa and 40%, respectively. By the detailed observation of the microstructure, the formation mechanism of the unique layered microstructure was found to be closely related to the repeated local heat treatment effect during the EBM process, and thus its control is further possible by the tuning-up of the process parameters. The results demonstrate that the EBM process enables not only the fabrication of TiAl products with complex shape but also the control of the tensile properties associated with the peculiar microstructure formed during the process.

Subfields: Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/db5ffa43621f233e29c88b0be2211fb26c4361d1

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In Materials Chemistry

1. Mingxing Zhang
2. H. Hallberg

In Mechanical Engineering

1. X. Tan
2. Shu Beng Tor
3. Han Huang
4. Pan Wang
5. Mingxing Zhang
6. M. Nai
7. Y. Kok
8. N. Loh

Citations in the corpus

• A Novel Strategy to Additively Manufacture 7075 Aluminium Alloy With Selective Laser Melting (2021, background): “Hence, highly dense brittle materials, such as TiAl intermetallic alloys can be additively manufactured [29].”
• Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review (2018, background): “Moreover, this layer band improves the ductility of Ti-48Al-2Nb-Cr alloy in a certain loading direction [42].”