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High-Temperature Deformation Behavior of the γ Alloy Ti-48Ai-2Cr-2Nb

Published online by Cambridge University Press:  26 February 2011

Donald S. Shih  and
Gary K. Scarr
Donald S. Shih
Affiliation:
GE Aircraft Engines, Mail Drop M-89, 1 Neumann Way, Cincinnati, Ohio 45215–6301, USA
Gary K. Scarr
Affiliation:
GE Aircraft Engines, Mail Drop M-89, 1 Neumann Way, Cincinnati, Ohio 45215–6301, USA
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Abstract

The hot-workability of a two-phase (γ+α2) alloy, Ti-48A1-2Cr-2Nb, has been studied by conducting isothermal compression tests to 0.8 true strain over the temperature range of 975–1200°C at strain rates between 1×l0−1 and 3×10−3s−1. A deformation map showing temperature, strain rate, soundness of deformation, and isostress contours was constructed. Good workability is found from the low temperature/low strain rate regime to combinations of high temperature and either high or low strain rate. The upper-limit flow stress for good workability is between 450 and 500 MPa. Deformation induced softening occurs at all conditions. SEM and TEM examinations of the deformed specimens reveal that non-uniform deformation takes place at all strain rates, but cracking occurs mostly at high strain rates (e.g. 1×10−1s−1), especially combined with low temperatures. The cracking appears to progress primarily along γ/α2interfaces. It is thought that non-uniform deformation develops channels of shear bands, which in turn promote localized recrystallization, thus accommodating higher strains.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 213: Symposium Q – High-Temperature Ordered Intermetallic Alloys IV , 1990 , 727
Copyright
Copyright © Materials Research Society 1991

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References

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