In-situ neutron diffraction characterization on the phase evolution of y-TiAl alloy during the wire-arc additive manufacturing process

Authors

Chen Shen, Shanghai Jiao Tong University, University of WollongongFollow
Klaus-Dieter Liss, University of Wollongong, Australian Nuclear Science and Technology Organisation, Israel Institute of TechnologyFollow
Mark H. Reid, Australian Nuclear Science and Technology OrganisationFollow
Zengxi Stephen Pan, University of WollongongFollow
Yan Ma, University of WollongongFollow
Xi Li, University of Wollongong, Australian Nuclear Science and Technology OrganisationFollow
Hui Jun Li, University of WollongongFollow

RIS ID

131825

Publication Details

Shen, C., Liss, K., Reid, M., Pan, Z., Ma, Y., Li, X. & Li, H. (2019). In-situ neutron diffraction characterization on the phase evolution of y-TiAl alloy during the wire-arc additive manufacturing process. Journal of Alloys and Compounds, 778 280-287.

Abstract

γ-phase based titanium aluminide has continuously been attractive because of its potential application in modern light-weight, high-temperature turbines, such as aircraft engines. However, it suffers from its poor plasticity and during manufacturing and processing. In recent years, wire-arc additive manufacturing process has been proved feasible of fabricating γ-phase based titanium aluminide structures with full density and relatively lower cost compared to traditional powder metallurgy processing. In the present research, the temperature process of a single-pass deposition process during the additive manufacturing was simulated as a linear heating (up to 1623 K) and cooling process in a vacuumed furnace, and in-situ investigated using neutron diffraction. As a result, compared to the initial as-fabricated state, the volume fraction of α2-phase increased by 2.54% after the heat treatment. Crystallographic aspects, specifically the α/α2 ↔ γ phase transformation and lattice evolutions of γ-phase are discussed in detail. According to the results obtained, the γ → α2 transition temperature in the present binary alloy is 1393 K, which largely deviates from earlier results collected from γ-phase based titanium aluminides with Nb addition. Also, the lattice evolutions of γ-phase in a function of time/temperature are linear fitted and responses of lattice strains (a, c axis and volumetric) to temperature are calculated.