Shape Memory Alloys
Mostrando 1-12 de 47 artigos, teses e dissertações.
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1. Microstructure and Thermal Analyses of Cu87-xAl13Nbx High-Temperature Shape Memory Alloys
This paper presents a thermal and microstructural characterization of Cu87-xAl13Nbx (wt%) high temperature shape memory alloys (HTSMA), with Nb contents ranging from 1 to 3%. The alloys were obtained by arc melting under argon atmosphere. Thermal characterization was performed by differential scanning calorimetry (DSC), revealing that the phase martensitic t
Mat. Res.. Publicado em: 28/11/2019
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2. Influence of Directional Solidification on the Mechanical Properties of Cu-Al-Be-Nb-Ni Alloy
Copper-based polycrystalline shape memory alloys (SMAs) have limitations for many practical applications due to their low superelasticity and low ductility. In order to overcome this situation, in recent years, the production of copper-based SMAs by directional solidification process has attracted the interest of many researches. In this sense, the present w
Mat. Res.. Publicado em: 05/09/2019
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3. Influence of Zirconium Percentage on Microhardness and Corrosion Resistance of Ti50 Ni50-xZrx Shape Memory Alloys
To obtain high temperature shape memory alloys of the lower cost Ni-Ti-X system, elements such as Hf and Zr are introduced to modify the thermal and mechanical properties of these alloys. This work studied the production and characterization of Ti50 Ni50-x Zrx alloys (x = 0, 5, 10 at.%) with the aim of improving their thermal, mechanical and corrosion resist
Mat. Res.. Publicado em: 19/08/2019
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4. Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
Abstract High transformation temperature shape-memory alloys (HTSMA) usually present a martensitic transformation temperature (Ms) starting at 100 ºC. That is the case of high nickel Ni-Ti-Hf alloys. This article presents experimental results obtained from arc melting of Ni50Ti50-XHfX .at% (X = 8, 11, 14, 17 and 20 .at%) alloys. This process homogenized eve
REM, Int. Eng. J.. Publicado em: 2019-06
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5. Nonlinear analysis of shape memory alloy beam under the thermal and the mechanical loads
ABSTRACT In this paper, the tension-compression asymmetry of shape memory alloys (SMA), subjected to the thermal and the mechanical loads, is sufficiently explored. Taking a basis of stress-strain relationship and a concern for critical phase transformation, a new simple model of mechanics is established. Through the deflection lines under different load con
Matéria (Rio J.). Publicado em: 20/05/2019
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6. Influence of defects on the irreversible phase transition in the Fe-Pd doped with Co and Mn
ABSTRACT The appearance of BCT martensite in Fe-Pd-based ferromagnetic shape memory alloys, which develops at lower temperatures than the thermoelastic martensitic transition, deteriorates the shape memory properties. In a previous work performed in Fe70Pd30, it was shown that a reduction in defects density reduces the non thermoelastic FCT-BCT transformatio
Matéria (Rio J.). Publicado em: 19/07/2018
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7. Study of the martensitic transition in Ni-Mn-Sn-Ti ferromagnetic shape memory alloys
ABSTRACT In the present work, mechanical spectroscopy measurements as a function of temperature and strain have been performed in (at.%) Ni50Mn37Sn13-xTix (x=0, 0.5 and 2) ferromagnetic shape memory alloys in order both to study martensitic transition phenomenon and also to determine its temperature of appearance. For mechanical spectroscopy measurements, a
Matéria (Rio J.). Publicado em: 19/07/2018
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8. Releasing systems for aerospace industry based upon Shape Memory Alloys: characterization of materials for actuators
ABSTRACT Releasing and deployment maneuvers carried out during space satellites launching are usually performed by utilizing pyrotechnics loads. However, it is considered convenient to replace this technique by others not requiring explosives (Non Explosive Actuators-NEA). This is mainly due to the necessity of reducing high-shock and vibrations induced leve
Matéria (Rio J.). Publicado em: 19/07/2018
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9. Impact of Alloy Composition and Thermal Stabilization on Martensitic Phase Transformation Structures in CuAlMn Shape Memory Alloys
Alloys of CuAlMn are known as cheap, high strength shape memory alloys with an excellent damping capacity within their austenitic-martensitic phase transformation, compared to alloy systems like NiTi, CuZnAl or MnCu. But CuAlMn alloys have disadvantage due to generation of voids by a high shrinkage which further increases the existing proneness to stress cra
Mat. Res.. Publicado em: 19/07/2018
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10. Microstructural Characterization of a Laser Surface Remelted Cu-Based Shape Memory Alloy
Cu-based shape memory alloys (SMAs) present some advantages as higher transformation temperatures, lower costs and are easier to process than traditional Ti-based SMAs but they also show some disadvantages as low ductility and higher tendency for intergranular cracking. Several studies have sought for a way to improve the mechanical properties of these alloy
Mat. Res.. Publicado em: 12/04/2018
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11. The Wire Drawing Mechanics of Near-Equiatomic NiTi SMA
The wire drawing mechanic of Ti-49.82Ni (at. %) Shape Memory Alloy (SMA) was investigated through the true stress-strain curves and drawing stresses. The tensile tested solution treated wire presented a four steps elongation at temperatures below the austenite finish temperature (AF), and a conventional one-step behavior above the martensite deformation temp
Mat. Res.. Publicado em: 26/03/2018
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12. Surface Characterization of NiTi Superelastic and Shape Memory Alloys After Electrolytic Polishing
For the biomedical application of NiTi alloys, an excellent surface finishing process is required to guarantee high corrosion resistance and biocompatibility, eliminating the allergenic and toxic effects associated with the release of nickel ions in the body. Electropolishing is a process that can reduce surface imperfections and form a thin protective layer
Mat. Res.. Publicado em: 09/11/2017