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On the Rate-dependency of Mechanical Properties and Failure Mechanisms of a (γ + α2) - TiAl/Ti3Al-Al2O3 Cermet
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- Author(s) / Creator(s)
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This study investigated the rate-dependent mechanical properties and failure of a self-propagating high-temperature synthesized TiAl/Ti3Al-Al2O3 cermet using mechanical testing and advanced microscopy. Quasi-static and dynamic uniaxial compression tests coupled with high-speed imaging and digital image correlation were used to determine the rate-dependency of stress-strain behavior, compressive strength, and failure strain. The stress-strain curves in the dynamic experiments exhibited a series of alternating stress relaxation and strain hardening cycles, where a ~ 1.2 times increase in compressive strength from 2780 ± 60 MPa to 3133 ± 265 MPa, and a ~ 1.6 times increase in failure strain from 0.0166 ± 0.0017 to 0.0264 ± 0.0032 were determined with an increase in strain rates from ~ 10−4 s−1 to ~ 103 s−1. It was also found that the cermet exhibits macroscopic surface texturing by examining the high-speed imaging of deformation during testing. Crystalline texturing with profound microstructural evolution in the titanium aluminide phase was found under dynamic loading using microscopy, and this was correlated with the macroscopic surface texturing observed using high-speed imaging and the cyclical stress relaxation and strain hardening behavior in the stress-strain curves. Altogether, this study presents a thorough understanding of the rate-dependency of the TiAl/Ti3Al-Al2O3 cermet with regard to mechanical properties and failure mechanisms and provides insights for modeling and improvement.
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- Date created
- 2020-07-01
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- Type of Item
- Article (Draft / Submitted)