Transformation-mismatch superplasticity in reinforced and unreinforced titanium
- Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering
Samples of commercial-purity titanium, with and without 10 vol.% TiC particulates, were thermally cycled about the allotropic transformation temperature of titanium. Thermal ratcheting was small for both unstressed materials. Upon application of an external uniaxial tensile stress, unreinforced titanium exhibited large strain increments, resulting from the biasing by the applied stress of the volume mismatch developed between grains during the transformation. Upon repeated cycling, a strain to fracture of 200% was reached, with a strain per cycle proportional to the external stress, in agreement with existing transformation-mismatch superplasticity models. The metal matrix composite displayed transformation-mismatch superplasticity as well, with a strain to fracture of 135% and a strain per cycle significantly higher than for unreinforced titanium. This novel enhancement of superplastic strain is modeled by considering the internal mismatch between the transforming matrix and the non-transforming particulates.
- OSTI ID:
- 215399
- Journal Information:
- Acta Materialia, Vol. 44, Issue 3; Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
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