Effect of composition and ageing on damping characteristics of Cu–Al–Mn shape memory alloys
15 Apr 2008-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing (Elsevier)-Vol. 478, Iss: 1, pp 48-55
TL;DR: In this paper, the damping behavior of the alloys was studied using a dynamic mechanical analyzer and it was shown that damping capacity increases with an increase in the aluminum content when the Cu/Mn ratio or amount of manganese is maintained constant.
Abstract: Cu–Al–Mn shape memory alloys in the range of 10–15 wt.% of aluminum and 0–10 wt.% of manganese, exhibiting β-phase at high temperatures and manifesting shape memory effect upon quenching to lower temperatures, were prepared through ingot metallurgy. The damping behavior of the alloys was studied using a dynamic mechanical analyzer. The damping capacity of the alloys increases with an increase in the aluminum content when the Cu/Mn ratio or amount of manganese is maintained constant. The damping capacity of the alloys decreases with an increase in the manganese content when the Cu/Al ratio or the amount of aluminum is maintained constant. The alloys exhibit an internal friction peak in the transition zone and that all of them exhibit higher damping capacity in the martensitic condition compared with that in the austenitic condition. While ageing of the alloys at 300 °C increases the transformation temperatures of the alloys, there is a reduction in the damping capacity of the alloys due to the formation of precipitates. The alloys aged at 500 °C do not exhibit the austenite to martensite transformation due to the formation of precipitates rich in aluminum and therefore exhibit very poor damping capacity.
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TL;DR: In this paper, a critical look at the science of shape memory phenomena as applicable to copper and iron based SMA systems is presented, which also covers the limitations of these systems, the effect of processing parameters on these alloys, proposed solutions to limitations associated with this group of SMA alloys and thoughts for future consideration.
84 citations
TL;DR: In this article, a ternary shape memory alloy with different amounts of quaternary elements Zn, Si, Fe, Pb, Ni, Mg, Cr and Ti were added to the base alloy.
82 citations
TL;DR: In this article, the effect of rare earth element Ce addition on the microstructure, martensitic transformation, mechanical properties and damping behavior of the Cu-Al-Mn shape memory alloys (SMAs) had been investigated.
45 citations
01 May 2012-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a thermal treatment that introduces nanoprecipitates in the shape-memory alloys was proposed to suppress 6R plastic deformation during the 18R −6R transformation.
Abstract: The 18R ↔ 6R martensite–martensite transformation in Cu-based alloys exhibits large hysteresis, large pseudoelastic strain and weak transformation stress dependence on temperature. However, concomitant plastic deformation taking place in the 6R phase inhibits the use of these properties for applications. A novel approach to minimizing or even suppressing 6R plastic deformation during the 18R–6R transformation in CuZnAl shape-memory alloy single crystals with electronic concentration e/a = 1.48 is presented. The method is based on a thermal treatment that introduces nanoprecipitates in the alloy. Results suggest that the role of CuZnAl shape-memory alloys in engineering should be reconsidered, as many energy damping applications could benefit from the huge hysteresis associated with the 18R–6R transformation, once the 6R plastic deformation is suppressed.
35 citations
TL;DR: In this article, the effect of solution temperature on martensite transformation temperatures, damping capacity and shape memory effect of a Cu-7.66Al-9.52Mn alloy was investigated by resistivity-temperature method, reversal torsion pendulum method and bend test.
33 citations
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TL;DR: In this article, the specific damping properties and damping functional behaviour of shape memory alloys, with special emphasis on NiTi, are discussed and illustrated by actual applications and applications under development.
315 citations
TL;DR: The ductile shape memory (SM) alloys of the Cu-AI-Mn system have been developed by controlling the degree of order in the β phase as mentioned in this paper, and they exhibit excellent ductility.
Abstract: Ductile shape memory (SM) alloys of the Cu-AI-Mn system have been developed by controlling the degree of order in the β phase. Additions of Mn to the binary Cu-Al alloy stabilize the β phase and widen the single-phase region to lower temperature and lower Al contents. It is shown that Cu-Al-Mn alloys with low Al contents have either the disordered A2 structure or the ordered L21 structure with a lower degree of order and that they exhibit excellent ductility. The disordered A2 phase martensitically transforms to the disordered Al phase with a high density of twins. The martensite phase formed from the ordered L21 phase has the 18R structure. The SM effect accompanies both the A2 → Al and L21 → 18R martensitic transformations. These alloys exhibit 15 pct strain to failure, 60 to 90 pct rolling reduction without cracking, and 80 to 90 pct recovery from bend test in the martensitic condition. Experimental results on the microstructure, crystal structure, mechanical properties, and shape memory behavior in the ductile Cu-AI-Mn alloys are presented and discussed.
207 citations
25 Jul 2004-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the ductile Cu-Al-Mn-based shape memory alloys (SMAs) have been used for guidewire applications and shown to have various properties of superelasticity, shape memory effect, two-way memory effect and internal friction.
Abstract: Recent progress on ductile Cu–Al–Mn-based shape memory alloys (SMAs) is presented. The various properties of superelasticity (SE), the shape memory effect (SME), the two-way memory effect (TWME) and internal friction are enhanced by controlling grain size and texture through thermomechanical treatments. It is also shown that the control of stress-induced martensitic transformation due to cold-rolling of Cu–Al–Mn SMAs results in low thermal expansion (LTE). In addition, the medical application of the Cu–Al–Mn-based SMAs to guidewire is introduced.
147 citations
TL;DR: In this article, the authors present a methodology for the analysis of the three terms of the internal friction spectrum, in light of theoretical models and observed experimental behavior, and discuss several conditions for the use of shape memory alloys as high damping materials in practical applications.
102 citations
15 Dec 1999-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effect of alloying elements on the shape memory properties of ductile shape memory (SM) alloys was investigated by differential scanning calorimetry, cold-rolling and tensile test techniques.
Abstract: The effect of alloying elements on the Ms temperature, ductility and the shape memory properties of Cu–Al–Mn ductile shape memory (SM) alloys was investigated by differential scanning calorimetry, cold-rolling and tensile test techniques. It was found that the addition of Au, Si and Zn to the Cu73–Al17–Mn10 alloy stabilized the martensite (6M) phase increasing the Ms temperature, while the addition of Ag, Co, Cr, Fe, Ni, Sn and Ti decreased the stability of the martensite phase, decreasing the Ms temperature. The SM properties were improved by the addition of Co, Ni, Cr and Ti.
91 citations