Compressive response of a single crystalline CoNiAl shape memory alloy

Karaca, H.E.

doi:10.1016/j.scriptamat.2004.04.002

Cited by 73 publications

(19 citation statements)

References 28 publications

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“…During unloading, reverse transformation occurs spontaneously since martensite is stable at such temperatures only under stress. Thus, removal of stress triggers martensite-to-austenite transition [78]. Consequently, the strain imposed during the loading is fully recovered upon unloading.…”

Section: Superelasticitymentioning

confidence: 99%

A revisit to atomistic rationale for slip in shape memory alloys

Chowdhury

Şehitoğlu

2017

Progress in Materials Science

113

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Performance degradation in shape memory alloys (SMA) arises due to a gradual loss of strain recoverability attributable to slip mediated plasticity. The slip-induced changes in SMAs can be profound creating accumulation of permanent strains, altering the critical stress and hysteresis in an adverse manner. Slip nucleation in ordered SMA lattices can often be triggered due to energetically favorable dissociation reactions. Partial slip can dominate over full slip, generating planar defects (e.g. anti-phase boundary, superlattice or complex stacking faults) as evidenced through electron microscopy. Considerable advances are made lately on physically rationalizing the observed plastic micromechanism(s) benefitting from quantum mechanical models. In-depth analyses of crystal variables (e.g. lattice ordering, atomic stacking and stable/metastable fault structures) subjected to intrinsic solid-state effects have unequivocally established the genesis of empirical slipping propensity in terms of atomic fault energetics. This article systematically revisits the empirical physical evidence of slip in important SMAs from the literature, presents the pertinent experimental findings, and then embarks on reviewing the

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Section: Superelasticitymentioning

confidence: 99%

A revisit to atomistic rationale for slip in shape memory alloys

Chowdhury

Şehitoğlu

2017

Progress in Materials Science

113

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“…Temperature dependent superelastic response of CoNiAl polycrystals were studied under compression where two stage phase transformation was observed at room temperature with superelastic strain of 4 % [11]. The orientation dependent behavior of CoNiAl single crystals were studied and it has been found that transformation strain is highly orientation dependent, a large superelastic temperature window of more than 150 °C can be observed in [100] orientation and there is huge tension-compression asymmetry [10,11,17,18]. Moreover, it was revealed that transformation strain decreases with stress and temperature [10] [19].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The decrease in superelastic strain attributed to the single variant formation at low temperature and the formation of multiple variants at high temperature. Although the mechanical characterization in terms of thermal cycling and superelastic behavior of CoNiAl alloys have been reported under compression and tension [10,11,17,23,24], orientation and temperature dependent shape memory behavior of CoNiAl alloys have not been systematically studied.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Although NiMnGa Heusler alloys can achieve high MFIS with low magnetic field, their extreme brittleness restricts their envisioned applications as magneto-actuators, sensors, caloric materials or energy harvesters. CoNiGa [6][7][8][9] and CoNiAl [10][11][12] alloys were developed as an alternative MSMA and they demonstrated high strength, stable behavior, low stress for variant reorientation, ability to alter transformation temperatures with heat treatments and high resistance to oxidation. The ductility of Co-based alloys were found to be improved mainly due to the existence of γ-phase (disordered fcc A1) [13].…”

Section: Introductionmentioning

confidence: 99%

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Orientation dependent compression behavior of Co35Ni35Al30 single crystals

Karaca

Chumlyakov

2017

Journal of Alloys and Compounds

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The shape memory effect (SME) and superelasticity (SE) behavior of homogenized Co 35 Ni 35 Al 30 single crystals were systematically characterized along the [100], [110] and [111] orientations under compression. The shape memory behavior of CoNiAl was found to be highly orientation and stress/temperature dependent. Maximum compressive recoverable strains were 3.98 % in [110], 3 % in [100] and 0.30 % in [111] orientations, respectively. The Co 35 Ni 35 Al 30 demonstrated a very high superelastic temperature window of more than 350 °C along the [100] and [110] orientations. Moreover, two-way shape memory effect with very low thermal hysteresis of about 6 °C was observed along the [110] orientation. The large decrease of recoverable strain and hysteresis with stress (or temperature) was mainly attributed to the difference of elastic moduli of transforming phases.

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“…The energy minimization approach assumes that the single crystal austenite transforms into martensite forming twinned martensite [20], while the lattice deformation approach assumes that the single crystal austenite transforms to single crystal martensite without internal twinning [21]. More detailed description of these theoretical frameworks can be found in [22][23][24][25][26]. Taking lattice parameters of austenite and martensite as 0.2903 nm and 0.3672 nm, respectively from [5], the calculated transformation strains with detwinning are found to be 26.5% and 14%, and the calculated CVP strains are 10.5% and 9% for the <100> and <123> orientations, respectively.…”

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confidence: 99%

Effects of crystallographic orientation on the superelastic response of FeMnAlNi single crystals

Tseng

Wang

et al. 2016

Scripta Materialia

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The effects of crystal orientation on the tensile superelastic response of the Fe 43.5 Mn 34 Al 15 Ni 7.5 single crystalline shape memory alloy, oriented along the <100> and <123> directions were investigated. The single crystals aged at 200°C for 3 hours demonstrated superelastic strains of 3.6% along the <100> orientation and 7.8% along the <123> orientation. Although the theoretical transformation strain in the <100> orientation is higher than that in the <123> orientation, the <123> oriented single crystals demonstrate better superelastic recovery in tension due to higher number of active martensite variants, which promotes better accommodation of internal strains and help minimize defect formation during transformation.

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Compressive response of a single crystalline CoNiAl shape memory alloy

Cited by 73 publications

References 28 publications

A revisit to atomistic rationale for slip in shape memory alloys

A revisit to atomistic rationale for slip in shape memory alloys

Orientation dependent compression behavior of Co35Ni35Al30 single crystals

Effects of crystallographic orientation on the superelastic response of FeMnAlNi single crystals

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