The behavior of internal markers in Ti-6Al-4V deformed in superplastic tension
- Univ. of Birmingham (United Kingdom). IRC in Materials for High Performance Applications
In the current work, internal markers were introduced into one of the best known superplastic materials, Ti-6 wt pct Al-4 wt pct V. Two sheets of 0.7-mm thickness were pressed into intimate contact after first cleaning the contacting surfaces and spraying a thin layer of an aqueous solution of Ca(OH){sub 2} onto one of those surfaces and allowing it to dry. The edges were joined using argon microplasma fusion welding and the assembly hot isostatically pressed at 900 C in a high purity argon atmosphere at 100 MPa for 90 minutes. Decomposition leaves particles of CaO at the interface, the remaining hydrogen and oxygen as well as any trapped atmospheric nitrogen and oxygen diffusing rapidly away from the interface into the bulk titanium. Specimens with a 35-mm parallel gage of 9.5-mm width were cut from the bonded sheet. These were tested in uniaxial tension at 920 C in air, with a layer of proprietary glaze to minimize the uptake of atmospheric elements. Extensions to strains of 0.4 and 1.0 were made at a strain rate of 10{sup {minus}4} s{sup {minus}1}. The strain rate was actually switched between values of 0.9 {times} 10{sup {minus}4} s{sup {minus}1} and 1.1 {times} 10{sup {minus}4} s{sup {minus}1}, with strain periods of 0.025 at each rate, to allow the strain rate sensitivity to be measured. The internal marker particles developed into small voids at the test temperature, even in the absence of deformation. The experimental observations are not consistent in the authors view, with grain boundary sliding having made any significant contribution to the deformation in the tensile tests.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 413304
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 27, Issue 11; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Characterization and analysis of low-temperature superplasticity in 8090 Al-Li alloys
Superplasticity and cavitation in Ti-6Al-4V alloy