Analysis of deformation behavior in beta titanium alloys using TEM in-situ observation

Deformation behavior has been studied in a multifunctional beta titanium alloy, Gum Metal, using in-situ nanopil-lar-compression tests in transmission electron microscope in comparison with a conventional beta titanium alloy, beta III. In-situ observations for dislocation activity and phase transformation during compression test of solution treated samples have been performed in bright-field and diffraction modes. Distinct contrast of dislocations has not been observed during the tests in bright field mode, however subtle contrast change, which might be related to dislocation motion, has been observed in localized areas of the Gum Metal specimen. In the diffraction mode, pre-existing diffraction from omega phase decreased, and diffraction from alpha double prime phase increased with increase amount of plastic deformation. In addition, a pillar of Gum Metal with large length-to-thickness ratio showed a large amount of pseudoelastic deformation after unloading. These results have been discussed in relation to deformation mechanisms in these beta titanium alloys. © 2019 The Japan Institute of Light Metals