Ordering transitions in quenched Au7Cu5Al4 alloy and effect of order on martensitic transformation

Jin, Min; Liu, Jiayi; Jin, Xuejun

doi:10.1016/j.intermet.2009.12.008

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…Therefore, the transformation observed by Jin et al [18] could only have been a B2 → DO 3 transition and not an A2 → DO 3 transformation. It is reported that the A2 → DO 3 and B2 → DO 3 transformations are almost inevitably first-order for reasons relating to symmetry [19] so if DO 3 phase did precipitate it should be apparent in microstructural sections or diffraction patterns.…”

Section: Structure Of Beta-quenched Materialsmentioning

confidence: 80%

“…For example, samples of Au 7 Cu 5 Al 4 aged between 100 and ∼150 • C have a well-developed shape-memory effect (as evidenced by significant transformation enthalpy, surface upheaval, dilatometric signal and acoustic emission), whereas samples produced by quenching from above 450 • C do not [11,[14][15][16][17]. X-ray diffraction showed that the strongly transforming samples possessed a parent phase with L2 1 ordering [14]-a condition that we will designate here as "fully aged" -but samples that have been quenched from elevated temperatures -a condition that we will designate here as "beta quenched" -have been reported to have the B2 structure [15] or mixtures of ordered phases of a nature intermediate between the A2, B2, L2 1 or DO 3 types [11,14,15,18]. Finally, metastable structures are reportedly formed when "beta-quenched" material is re-heated [18].…”

Section: Introductionmentioning

confidence: 99%

“…X-ray diffraction showed that the strongly transforming samples possessed a parent phase with L2 1 ordering [14]-a condition that we will designate here as "fully aged" -but samples that have been quenched from elevated temperatures -a condition that we will designate here as "beta quenched" -have been reported to have the B2 structure [15] or mixtures of ordered phases of a nature intermediate between the A2, B2, L2 1 or DO 3 types [11,14,15,18]. Finally, metastable structures are reportedly formed when "beta-quenched" material is re-heated [18].…”

Section: Introductionmentioning

confidence: 99%

“…Jin et al examined Au 7 Cu 5 Al 4 quenched from 680 • C and concluded [18] that it ordered to DO 3 rather than L2 1 when re-heated up through the range 172-281 • C. A depression of the M s from about 0 • C to −35 • C was attributed to the presence of this DO 3 parent. The structure above 630 • C was believed to be A2.…”

Section: Introductionmentioning

confidence: 99%

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High temperature transformations of the Au7Cu5Al4 shape-memory alloy

Cortie

Kealley

Bhatia

et al. 2011

Journal of Alloys and Compounds

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a b s t r a c tThe ␤-phase of Au 7 Cu 5 Al 4 undergoes a reversible shape-memory phase transformation, however there has been some uncertainty regarding the crystal structure or structures of the parent phase. Here we show that, under equilibrium conditions, the parent phase possesses the L2 1 structure between its A p (about 79 • C) and ∼630 • C, and the B2 primitive cubic structure between ∼630 • C and its melting point. It melts directly from B2 into the liquid state and hence never achieves the random bcc A2 structure that has been previously mooted. Splat-cast samples of the alloy are martensitic, proving that development of equilibrium order and defect concentration are not pre-requisites for the A → M transformation to occur.

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Section: Structure Of Beta-quenched Materialsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High temperature transformations of the Au7Cu5Al4 shape-memory alloy

Cortie

Kealley

Bhatia

et al. 2011

Journal of Alloys and Compounds

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“…It has been shown to be relatively resistant to aging compared to its copper-based counterparts and has been previously studied in its bulk form [2][3][4][5][6][7][8][9][10][11][12]. However no work has been done on any thin film or nanostructured properties.…”

Section: Introductionmentioning

confidence: 99%

Thin Films of AuCuAl Shape Memory Alloy for Use in Plasmonic Nano-actuators

et al. 2011

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We describe the fabrication and structure of nanoscale thin films of β phase shape memory alloys with the nominal atomic stoichiometry Au 7 Cu 5 Al 4 (corresponding to 5.8 wt% Al). These alloys possess properties that suggest they could be used in nanoscale actuators. The films described here are between 20 and 50 nm thick which is below the thickness at which some other shape memory alloys cease to transform. However, microstructural and X-ray studies confirm that the coatings still exhibit the displacive transformations that are a prerequisite for the shape memory effect.

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Composition–Structure–Property Relations in Au35–68Cu49–15Al16–17 Shape Memory Thin Films

Buenconsejo

Pfetzing‐Micklich

Paulus

et al. 2016

Shap. Mem. Superelasticity

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The phase transformation behaviour, structure and mechanical properties of Au 35-68 Cu 49-15 Al 16-17 thin film shape memory alloys (SMA) have been investigated, with emphasis on the effects of Au content. The results revealed the underlying composition-structure-property relations. The thermal transformation hysteresis (DT) is wide (*55 K) for thin films with Au \50 at.%, while it is narrow (*15 K) for thin films with Au [50 at.%. This behaviour is correlated with the change in lattice constant of b-(Au-Cu-Al) (a b), suggesting a structural origin on the DT behaviour. The mechanical properties, such as hardness and elastic modulus, varied in the range of 2-4 and 70-120 GPa, respectively. The optimum Au composition range for tuning the functional property is between 43 and 55 at.% Au, where the least amount of non-transforming phases form and DT can be tailored between 55 K (43 at.% Au) and 17 K (55 at.% Au). This is important for the development and practical application of Au-Cu-Al based thin film SMA.

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Ordering transitions in quenched Au7Cu5Al4 alloy and effect of order on martensitic transformation

Cited by 7 publications

References 18 publications

High temperature transformations of the Au7Cu5Al4 shape-memory alloy

High temperature transformations of the Au7Cu5Al4 shape-memory alloy

Thin Films of AuCuAl Shape Memory Alloy for Use in Plasmonic Nano-actuators

Composition–Structure–Property Relations in Au35–68Cu49–15Al16–17 Shape Memory Thin Films

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