Transformation-mismatch superplasticity in reinforced and unreinforced titanium

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(95)00224-3· OSTI ID:215399

Dunand, D C; Bedell, C M ^[1]

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1. 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, Journal Name: Acta Materialia Journal Issue: 3 Vol. 44; ISSN XZ504Y; ISSN 1359-6454
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
FRACTURES
MATHEMATICAL MODELS
PARTICULATES
PHASE TRANSFORMATIONS
PLASTICITY
STRAINS
STRESSES
THERMAL CYCLING
TITANIUM
TITANIUM CARBIDES