Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

Adorno, A. T.; Benedetti, Assis Vicente; Silva, R. A. G. da; Blanco, Matildes

doi:10.1590/s0100-46702003000100004

Cited by 12 publications

(4 citation statements)

References 12 publications

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“…The other sophisticated problem is nucleation and growth of pearlite colonies, which is a particular case of a more general issue of eutectoid decomposition. Transformations of this type are also observed in Zn-Al [50], Cu-Al [51], Au-In [52], Cu-Zn, Al-Mn, Cu-Sn, Cu-Be, etc., and the precipitates morphology (lamellar or globular structure) depends on the type of alloy and the position of alloy parameters on the phase diagram. Although the pearlite transformation (PT) in [35].…”

Section: Current Understanding Of Phase Transformations In Iron and Smentioning

confidence: 85%

Towards the ab initio based theory of phase transformations in iron and steel

Razumov

Gornostyrev

Katsnelson

2017

Phys. Metals Metallogr.

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Despite of the appearance of numerous new materials, the iron based alloys and steels continue to play an essential role in modern technology. The properties of a steel are determined by its structural state (ferrite, cementite, pearlite, bainite, martensite, and their combination) that is formed under thermal treatment as a result of the shear lattice reconstruction γ (fcc) → α (bcc) and carbon diffusion redistribution. We present a review on a recent progress in the development of a quantitative theory of the phase transformations and microstructure formation in steel that is based on an ab initio parameterization of the Ginzburg-Landau free energy functional. The results of computer modeling describe the regular change of transformation scenario under cooling from ferritic (nucleation and diffusion-controlled growth of the α phase) to martensitic (the shear lattice instability γ → α). It has been shown that the increase in short-range magnetic order with decreasing the temperature plays a key role in the change of transformation scenarios. Phase-field modeling in the framework of a discussed approach demonstrates the typical transformation patterns.

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Section: Current Understanding Of Phase Transformations In Iron and Smentioning

confidence: 85%

Towards the ab initio based theory of phase transformations in iron and steel

Razumov

Gornostyrev

Katsnelson

2017

Phys. Metals Metallogr.

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“…Pearlite transformation (PT) is an example of eutectoid decomposition which was observed also in many non-ferrous alloys [3][4][5] below some critical (eutectoid) temperature. Despite numerous studies of PT motivated by its great practical importance for metallurgy, the mechanism of formation of the regular lamellar structure remains unclear.…”

Section: Introductionmentioning

confidence: 99%

Autocatalytic Mechanism of Pearlite Transformation in Steel

2017

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A model of pearlite colony formation in carbon steels with ab-initio parameterization is proposed. The model describes the process of decomposition of austenite and cementite formation through a metastable intermediate structure by taking into account the increase of the magnetic order under the cooling. Autocatalytic mechanism of pearlite colony formation and the conditions for its implementation have been analyzed. We demonstrate that pearlite with lamellar structure is formed by autocatalytic mechanism when thermodynamic equilibrium between the initial phase (austenite) and the products of its decomposition (cementite and ferrite) does not take place. By using model expression for free energy with first-principles parameterization we find conditions of formation of both lamellar and globular structures, in agreement with experiment. The transformation diagram is suggested and different scenarios in the kinetics of decomposition are investigated by phase field simulations. 64.60.My, 75.50.Bb

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“…Higher quantities of Mn with the presence of Ag resulted in β 3 phase, which exhibits magnetic properties. With the increase of Al content, β phase decomposition reduces and there will be a higher possibility for phases with lower symmetry (Adorno et al , 2003). Other reasons that reduce the SME are dislocations, vacancies formed during quenching.…”

Section: Introductionmentioning

confidence: 99%

Effect of alloying constituents on thermal, microstructural, mechanical and shape memory properties of Cu-Al-Ag shape memory alloys

Tataverthi¹,

Devisetty²

2022

WJE

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Purpose The purpose of this study is to assess the influence of Al and Ag addition on thermal, mechanical and shape memory properties of Cu-Al-Ag alloy. Design/methodology/approach The material is synthesized in a controlled atmosphere to minimize the reaction of alloying elements with the atmosphere. Cast samples were homogenized, then subjected to hot rolling and further betatized, followed by step quenching. Eight samples were chosen for study among which first four samples varied in Al content, and the next set of four samples varied in Ag composition. Findings The testing yielded a result that the increase in binary alloying element decreased transformation temperature range but increased entropy and elastic energy values. It also improved the shape memory effect and mechanical properties (UTS and hardness). An increase in ternary alloying element increased transformation temperature range, entropy and elastic energy values. The shape memory effect and mechanical properties are enhanced by the increase in ternary alloying element. The study revealed that compositional variation of Al should be limited to a range of 8 to 14 Wt.% and Ag from 2 to 8 Wt.%. Microstructural and diffraction studies identified the ß’1 martensite as a desirable phase for enhancing shape memory properties. Originality/value Numerous studies have been made in exploring the transformation temperature and phase formation for similar Cu-Al-Ag shape memory alloys, but their influence on shape memory effect was not extensively studied. In the present work, the influence of Al and Ag content on shape memory characteristics is carried out to increase the design choice for engineering applications of shape memory alloy. These materials exhibit mechanical and shape memory properties within operating ranges similar to other copper-based shape memory alloys.

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Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

Cited by 12 publications

References 12 publications

Towards the ab initio based theory of phase transformations in iron and steel

Towards the ab initio based theory of phase transformations in iron and steel

Autocatalytic Mechanism of Pearlite Transformation in Steel

Effect of alloying constituents on thermal, microstructural, mechanical and shape memory properties of Cu-Al-Ag shape memory alloys

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