Stress dependence of the hysteresis in single crystal NiTi alloys

Hamilton, Reginald F.; Şehitoğlu, Hüseyin; Chumlyakov, Y. I.; Maier, Hans Jürgen

doi:10.1016/j.actamat.2004.03.038

Cited by 321 publications

(164 citation statements)

References 21 publications

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“…In particular, a detailed analysis reveals that transformation-induced dislocations have Burgers vectors and slip planes with rationale directions in the austenite basis rather than the martensite basis [27]. These observations follow earlier work documenting the formation of planar dislocation arrays during loadbiased thermal cycling of 50.1 and 50.4 at.% Ni-Ti [30]. Plastic deformation has also been proposed to explain progressive widening of the {1 1 0} B2 peak during load-biased thermal cycling [31].…”

Section: Introductionsupporting

confidence: 68%

“…For comparison, simulations using the Patoor et al [23] structure for h tu substantially overestimate E T at small R bias (curve h tu (Patoor) , Fig. 6) and predict E T to be relatively independent of R bias , contrary to these and previous experimental results [1][2][3]30].…”

Section: Effect Of Bias Stress and Prestrain On Transformation Straincontrasting

confidence: 47%

“…In principle, martensite plasticity can also be incorporated, but detailed experimental evidence of operative slip systems and critical stresses for activation is lacking. Given the recent observations of complex dislocation structures induced by transformation [25,29,30], it is remarkable that an aggregate-based, grain-scale model is so successful.…”

Section: Discussionmentioning

confidence: 99%

“…On this smaller scale, retained martensite can affect texture evolution, and the stress redistribution in the vicinity of the plates may promote dislocation substructure [27][28][29][30] and affect the critical driving force for martensite formation (f c , Eq. (9)).…”

Section: Discussionmentioning

confidence: 99%

“…This discrepancy may be due to the nature of the "aggregate" constitutive relation (Section 3.2.3) and the assumption that the rate of slip activity (_ c s , Section 3.2.4) and rate of martensite formation (_ m t , Section 3.2.5) are both computed from the average aggregate stress. In reality, the local stress field around martensite plates can be sufficiently large to drive local plasticity, as evidenced by recent transmission electron microscopy of dislocation content in micron-scale, pseudoelastically compressed single crystals [27] and load-biased thermal cycling of larger single crystals [30].…”

Section: Discrepancy In Open Loop Strainmentioning

confidence: 99%

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Thermal cycling and isothermal deformation response of polycrystalline NiTi: Simulations vs. experiment

et al. 2011

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A recent microstructure-based FEM model that couples crystal-based plasticity, the B2 M B19 0 phase transformation and anisotropic elasticity at the grain scale is calibrated to recent data for polycrystalline NiTi (49.9 at.% Ni). Inputs include anisotropic elastic properties, texture and differential scanning calorimetry data, as well as a subset of recent isothermal deformation and load-biased thermal cycling data. The model is assessed against additional experimental data. Several experimental trends are captured -in particular, the transformation strain during thermal cycling monotonically increases and reaches a peak with increasing bias stress. This is achieved, in part, by modifying the martensite hardening matrix proposed by Patoor et al. [Patoor E, Eberhardt A, Berveiller M. J Phys IV 1996;6:277]. Some experimental trends are underestimated -in particular, the ratcheting of macrostrain during thermal cycling. This may reflect a model limitation that transformation-plasticity coupling is captured on a coarse (grain) scale but not on a fine (martensitic plate) scale.

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Section: Introductionsupporting

confidence: 68%