Phase fraction, texture and strain evolution in superelastic NiTi and NiTi-TiC composites investigated by neutron diffraction

Journal Article · Wed Sep 29 04:00:00 EDT 1999 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00214-1· OSTI ID:20000478

Vaidyanathan, R; Bourke, M A.M.; Dunand, D C

Samples of superelastic NiTi and superelastic NiTi reinforced with 10 vol.% TiC particles were deformed under uniaxial compression to 975 MPa while neutron diffraction spectra were simultaneously collected. Despite the presence of stiff TiC particles, a macroscopic strain of 3% was obtained in the composite on loading and was fully recovered on unloading. The diffraction spectra were analyzed by Rietveld refinement that included a spherical harmonic description of the texture and a lattice plane (hkl) dependent formulation of the elastic strain. The experiments provided bulk, phase-specific measurements of the volution of phase fractions, texture and strains during the reversible stress-induced austenite to martensite transformation responsible for the large recoverable strains. For the composite, Eshelby elastic theory is used to predict the discrete phase strains measured by neutron diffraction. The observed behavior suggests that the martensite accommodates the mismatch with the transforming austenite (while they co-exist) and the TiC particles (in the case of the composite).

• Research Organization: Massachusetts Inst. of Tech., Cambridge, MA (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 20000478
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 12 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRYSTAL-PHASE TRANSFORMATIONS
ELASTICITY
NEUTRON DIFFRACTION
NICKEL ALLOYS
SHAPE MEMORY EFFECT
TEXTURE
TITANIUM ALLOYS
TITANIUM CARBIDES