Anomalous transformation-induced deformation in 〈1 1 0〉 textured Gum Metal

Morris, J. W.; Hanlumyuang, Yuranan; Sherburne, Matthew; Withey, Elizabeth Ann; Chrzan, D. C.; Kuramoto, Shigeru; Hayashi, Yukimasa; Hara, Masashi

doi:10.1016/j.actamat.2010.02.001

Cited by 68 publications

(48 citation statements)

References 10 publications

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“…A solution treated followed by water-quenched single crystal with the composition of Ti-36(23)Nb-2(0.6)Ta-3(2)Zr-0.3(1.2)O (mass% (mol%)), grown in ©111ª direction by floating zone melting 6) was cut into compression specimens with a size ³1 mm © 1 mm © 2 mm. The compression axis was close to ©111ª direction.…”

Section: Methodsmentioning

confidence: 99%

“…The reason for the selection of this particular orientation is that the stress induced ¢ ¼ ¡ martensitic transformation is not expected for this orientatiion. 6) After polishing the surfaces, the single crystals were compressed at a strain rate of 4 © 10 ¹4 s ¹1 at temperatures between 77 K and 450 K in a cryostat or in a furnace. Since Gum Metal alloys exhibit little work hardening, the temperature dependence of the yield stress can be obtained rather accurately from the change of the flow stress accompanying the temperature change for the same specimen.…”

Section: Methodsmentioning

confidence: 99%

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Thermally Activated Deformation of Gum Metal: A Strong Evidence for the Peierls Mechanism of Deformation

et al. 2015

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Compression deformation and stress relaxation tests have been made over a wide temperature range for Ti-based bcc alloy single crystal of Gum Metal composition to elucidate the deformation mechanism. The shear yield stress decreases rapidly with increasing temperature with decreasing slope above room temperature, tending to level off. Activation analysis showed that the activation volume becomes smaller than 10 b 3 (b: the Burgers vector) at high stress, indicating that the deformation is controlled by the Peierls mechanism at low temperature. Similar results have been obtained also for severely cold-swaged polycrystalline Gum Metal with the similar composition. These results contradict the generally accepted dislocation-free mechanism of Gum Metal.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Thermally Activated Deformation of Gum Metal: A Strong Evidence for the Peierls Mechanism of Deformation

et al. 2015

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“…The habit plane of the stress-induced phase in Fig. 4 is different from those of α phase 38) and usual {112}〈111〉 twin, but is consistent with {332}〈113〉 twin. {312}〈113〉 twin formation was reported, in addition to α -phase and ω-phase, by Yang et al in deformed microstructure of Gum Metal 39) , but massive {332}〈113〉 twin formation determining the macroscopic yield stress of Gum Metal at low temperature was rst observed in this paper.…”

Section: Deformation Mechanism Of Single Crystalsmentioning

confidence: 85%

Basic Deformation Mechanism of Bcc Titanium-Based Alloy of Gum Metal

et al. 2016

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Single crystals and cold-swaged polycrystalline specimens of Gum Metal of Ti-36Nb-2Ta-3Zr-0.3O (mass %) have been compressed with the stress-relaxation test in the temperature range from 77 K to 450 K. In both single crystals and cold-swaged specimens, the yield stress decreases with increasing temperature rapidly to the room temperature and then gently above it forming a plateau at high temperature. The activation analysis of plastic deformation showed that the applied shear stress dependence of activation enthalpy and that of activation volume for single crystals and those for cold swaged specimens are almost identical if we shift the stress scale by about 120 MPa, meaning that the basic deformation mechanism is common to both samples. The above results are contradictory with the previously proposed non-dislocation deformation mechanism at the ideal shear strength, but consistent with the established features of usual bcc alloys, i.e., the deformation is governed by the Peierls mechanism at low temperature and by defect hardening at high temperature. τ χ − χ and ψ − χ relations of single crystals showed a typical slip asymmetry seen in bcc metals, where slip in Gum Metal belongs to the {112} slip type as in binary Ti-Nb single crystals reported previously (S. Hanada et al.: Metall. Trans. A 16 (1985) 789). Yielding by massive {332}〈113〉 twin formation in single crystals at low temperatures was observed for the rst time in Gum Metal.

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“…Crystallographic texture [15,16] and cold work prior to testing [17] have both been reported to influence the superelastic properties of these alloys, as they affect the martensitic transformation. The superelastic strain is determined by the martensite variants that form in response to the applied stress, and, therefore, related to the orientation of the parent grains.…”

Section: Introductionmentioning

confidence: 99%

The Behaviour of Gum Metal (Ti‐36Nb‐2Ta‐3Zr‐0.3O wt.%) During Superelastic Cycling

Jones

Vorontsov

Dye

2016

Proceedings of the 13th World Conference on Titanium

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Metastable beta titanium alloys, such as Gum Metal (Ti-36Nb-2Ta-3Zr-0.3O wt.%), have received significant attention from the biomedical field over the last decade due to their low elastic modulus. Despite initial scepticism, it is now widely accepted that these alloys undergo a stress-induced transformation when subjected to an applied load, forming an orthorhombic martensite phase within the beta matrix. The reversible nature of this transformation gives rise to superelasticity, which is of significant interest for engineering applications outside of the biomedical industry. However, little is known as to the stability of the superelastic behaviour with respect to repeated load cycling. Here the response of Gum Metal during superelastic cycling was studied in situ, using high energy synchrotron diffraction. The material was observed to accumulate permanent damage with every cycle and the critical stress required for transformation decreased. The diffraction data was used to track the evolution of the martensite phase, both as a function of applied stress and cycle number. The martensite that formed was highly textured, with two independent orientations observed on each Debye-Scherrer ring. These orientations formed at different applied stresses and had different volume fractions at the peak stress. The volume fraction at the peak stress of all martensite orientations increased with cycling, which is believed to increase the defect concentration in the material and hence influence the deformation behaviour.

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Anomalous transformation-induced deformation in 〈1 1 0〉 textured Gum Metal

Cited by 68 publications

References 10 publications

Thermally Activated Deformation of Gum Metal: A Strong Evidence for the Peierls Mechanism of Deformation

Thermally Activated Deformation of Gum Metal: A Strong Evidence for the Peierls Mechanism of Deformation

Basic Deformation Mechanism of Bcc Titanium-Based Alloy of Gum Metal

The Behaviour of Gum Metal (Ti‐36Nb‐2Ta‐3Zr‐0.3O wt.%) During Superelastic Cycling

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