Low-temperature superplasticity of ultra-fine-grained Ti-6Al-4V processed by equal-channel angular pressing
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SCOPUS
- Title
- Low-temperature superplasticity of ultra-fine-grained Ti-6Al-4V processed by equal-channel angular pressing
- Authors
- Ko, YG; Lee, CS; Shin, DH; Semiatin, SL
- Date Issued
- 2006-02
- Publisher
- MINERALS METALS MATERIALS SOC
- Abstract
- The low-temperature superplasticity of ultra-fine-grained (UFG) Ti-6Al-4V was established as a function of temperature and strain rate. The equiaxed-alpha grain size of the starting material was reduced from 11 to 0.3 mu m (without a change in volume fraction) by imposing an effective strain of similar to 4 via isothermal, equal-channel angular pressing (ECAP) at 873 K. The ultrafine microstructure so produced was relatively stable during annealing at temperatures up to 873 K. Uniaxial tension and load-relaxation tests were conducted for both the starting (coarse-grained (CG)) and UFG materials at temperatures of 873 to 973 K and strain rates of 5 X 10(-5) to 10(-2) s(-1). The tension tests revealed that the UFG structure exhibited considerably higher elongations compared to those of the CG specimens at the same temperature and strain rate. A total elongation of 474 pct was obtained for the UFG alloy at 973 K and 10(-4) s(-1). This fact strongly indicated that low-temperature superplasticity could be achieved using an UFG structure through an enhancement of grain-boundary sliding in addition to strain hardening. The deformation mechanisms underlying the low-temperature superplasticity of UFG Ti-6Al-4V were also elucidated by the load-relaxation tests and accompanying interpretation based on inelastic deformation theory.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/11511
- DOI
- 10.1007/s11661-006-0008-z
- ISSN
- 1073-5623
- Article Type
- Article
- Citation
- METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, vol. 37A, no. 2, page. 381 - 391, 2006-02
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