Macroscopic shape change of Cu13Zn15Al shape memory alloy on successive heating

Li, Z.; Gong, Shen; Wang, M.P.

doi:10.1016/j.jallcom.2006.11.026

Cited by 22 publications

(14 citation statements)

References 16 publications

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“…It has been observed that electron diffraction patterns exhibit similar characteristics, but some changes occur at the diffraction angles and intensities on the x-ray diffractograms with aging duration. These changes occur as rearrangement or redistribution of atoms in the material, and attribute to new transitions in diffusive manner [3][4][5]. In particular, some of the neighbor peak pairs have moved toward each other.…”

Section: Resultsmentioning

confidence: 99%

Lattice Reactions Governing Thermoelasticity and Superelasticity in Shape Memory Alloys

Adigüzel¹

2021

PSBJ

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Some materials take place in class of advanced smart materials with adaptive properties and stimulus response to the external changes. Shape memory alloys take place in this group, due to the shape reversibility and capacity of responding to changes in the environment. These alloys exhibit a peculiar property called shape memory effect, which is characterized by the recoverability of two certain shapes of material at different temperatures. These alloys have dual characteristics called thermoelasticity and superelasticity, from viewpoint of memory behavior, which is governed by two structural transformations, thermal and stress induced martensitic transformations performed by lattice twinning and detwinning reactions. Thermal induced transformation is governed by lattice twinning and occurs on cooling and ordered parent phase structures turn into twinned martensite structures, and these twinned structures turn into detwinned martensite structures by means of strain induced martensitic transformation, by stressing material in low temperature condition. Superelasticity is performed by stressing and releasing material at a constant temperature in parent phase region, and shape recovery is performed simultaneously upon releasing the applied stress.

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Section: Resultsmentioning

confidence: 99%

Lattice Reactions Governing Thermoelasticity and Superelasticity in Shape Memory Alloys

Adigüzel¹

2021

PSBJ

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“…It has been observed that electron diffraction patterns exhibit similar characteristics, but some changes occur at the peak locations and intensities on the x-ray diffractograms with aging duration. These changes occur as rearrangement or redistribution of atoms in the material, and attribute to new transitions in diffusive manner [4], [7], [11]. The ordered structure or super lattice structure is essential for the shape memory quality of the material.…”

Section: Methodsmentioning

confidence: 99%

“…In order to make the material satisfactorily ordered and to delay the martensite stabilization, copper-based shape memory alloys are usually treated by step-quenching after homogenization. Metastable phases of copper-based shape memory alloys are very sensitive to the ageing effects, and any heat treatment can change the relative stability of both martensite and parent phases [11], [12]. Martensite stabilization is closely related to the disordering in martensitic state.…”

Section: Methodsmentioning

confidence: 99%

Thermoelastic and Pseudoelastic Characterization of Shape Memory Alloys

Adigüzel¹

2017

IJMSE

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Shape-memory effect is based on martensitic transformation, which is a solid state phase transformation and govern the remarkable changes in internal crystalline structure of materials. Shape memory alloys can exhibit another property called pseudoelasticity (PE), which is performed in only mechanical manner in the parent austenite phase region. Shape Memory Effect (SME) is performed thermally in a temperature interval and this behaviour is called thermoelasticity. Pseudoelasticity is performed by stressing the material in the parent phase region, and shape recovery is performed simultaneously upon releasing the applied stress. PE is the result of stress-induced martensitic transformation. Martensitic transformations occur with cooperative movement of atoms by means of lattice invariant shear which occurs in two opposite directions on close packed planes of parent austenite phase, and possible 24 martensite variants occur. By this way the twinned martensite occurs on cooling, and the twinned structure turn into the detwinned martensite by deformation in the low temperature product phase condition. Copper based alloys exhibit this property in metastable beta-phase region, which has bccbased structures at high temperature parent phase field, and these structures martensiticaly turn into layered complex structures with lattice twinning on cooling.

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“…10 The main disadvantage in exploiting the applications of Cu-Zn-Al based SMAs, as functional materials, is diffusion controlled martensite stabilisation, which occurs on successive heating even in a low temperature range. 11 This stabilisation phenomenon causes the shift of the critical temperatures for reverse martensitic transformation (A s and A f ) to higher temperatures. 12 In a recent study, on a Cu-Zn-Al SMA subjected to thermal cycling with free air cooling, thermal memory degradation was associated with an alteration of martensite reversion to parent phase which experienced three variation tendencies, during repetitive heating:…”

Section: Introductionmentioning

confidence: 99%

“…However, several drawbacks, caused by metallurgical processing,4 training5 or cycling,6 limited the development of the applications of Cu–Zn–Al based SMAs to single triggering devices such as couplings7 or high work output thermal actuators8 for fire protection9 or for temperature monitoring in freezing chambers 10. The main disadvantage in exploiting the applications of Cu–Zn–Al based SMAs, as functional materials, is diffusion controlled martensite stabilisation, which occurs on successive heating even in a low temperature range 11. This stabilisation phenomenon causes the shift of the critical temperatures for reverse martensitic transformation ( A s and A f ) to higher temperatures 12.…”

Section: Introductionmentioning

confidence: 99%

On role of atomic migration in amnesia occurrence during complex thermal cycling of Cu–Zn–Al shape memory alloy

Bujoreanu¹,

Lohan²,

Pricop³

et al. 2012

Materials Science and Technology

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The reproducibility of thermally induced reversible martensitic transformation, occurring in a Cu–15Zn–6Al (mass-) shape memory alloy during heating, was studied on three different fragments of martensitic alloy subjected to complex thermal cycling comprising four series of five heating–cooling cycles, applied on a differential scanning calorimetry (DSC) device, between room temperature (RT) and three maximum temperatures: 453, 463 and 473 K respectively. After each series of heating–cooling cycles the fragments were naturally aged at RT for 37 days (∼3·2 Ms). Thermograms of DSC revealed a gradual diminution in the magnitude of martensite reversion to parent phase, accompanied by decreasing tendencies of both critical temperatures and transformation rates, which reflect a gradual loss of thermal memory, associated with ‘amnesia’ occurrence. Scanning electron microscopy observations coupled with energy dispersive X-ray spectroscopy performed at the end of complex thermal cycling revealed that ‘amnesia’ occurrence was associated with changes in the morphology of martensite plates, from parallel plate-like to interblocking needle-like, and with an increase of chemical fluctuations, as an effect of the intensification of atomic migration.

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Macroscopic shape change of Cu13Zn15Al shape memory alloy on successive heating

Cited by 22 publications

References 16 publications

Lattice Reactions Governing Thermoelasticity and Superelasticity in Shape Memory Alloys

Lattice Reactions Governing Thermoelasticity and Superelasticity in Shape Memory Alloys

Thermoelastic and Pseudoelastic Characterization of Shape Memory Alloys

On role of atomic migration in amnesia occurrence during complex thermal cycling of Cu–Zn–Al shape memory alloy

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