Ti-Ta High Temperature Shape Memory Alloys

Chilnicean, G; Novac, Andrei; Sprincenatu, Roxana; Bolocan, Vlad; Crăciunescu, Corneliu Marius

doi:10.1088/1757-899x/416/1/012017

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…In addition to the strong β-phase peaks, a few weak peak are observed for alloy after cold rolling and recrystallizing (CR +RE), which can be indexed as αʺ martensite with an orthormbic crystal structure at room temperature. Our results are consisted with the data reported in literatures [21][22][23]. Materials and Technologies in Modern Production…”

Section: Phase Characterizationsupporting

confidence: 87%

Effect of Oxidation on the Transformation Temperatures and Microstructure of Ti-Ta-Al High Temperature Shape Memory Alloys

Khulief

Mahdy

2022

KEM

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In this study, the effect of oxidation on the transformation temperatures and microstructure of Ti-Ta20-Al5 high temperature shape memory alloys (Ti-Ta20-Al5 HTSMAs) is studied. The alloy was studied under two conditions, as cast and after cold rolling and recrystallizing (CR +RE). The microstructure, phase composition, and phase transformation temperature of Ti-Ta20-Al5 HTSMAs before oxidation were studied. Thermogravimetric analysis (TGA) combination with microstructural investigations were performed after oxidation at temperatures range from 25°C up to 1000°C. For both conditions, the alloy consisted mostly of β – BCC and martensite ʺα – orthorhombic phase before oxidation. Ti-Ta20-Al5HTSMAs as (CR +RE) shows martensitic transformation temperature higher than 400°C. The oxidation behaviour was linear until 650°C, while parabolic at elevated temperatures. For both conditions, the alloy consisted of β – BCC phase (Ta – rich) and α-hexagonal phase (Ti – rich) with not strong precipitation of ω – phase after oxidation. The results show that the formation of multi – layer oxide, which consists of Al2O3, TiO2, and Ta2O5. For both conditions, oxidation can suppress martensitic phase transformation by precipitation of α-hexagonal phase (Ti – rich), Al2O3, TiO2, and Ta2O5, and ω phase, would result in degradation of the martensitic phase transformation.

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Section: Phase Characterizationsupporting

confidence: 87%

Effect of Oxidation on the Transformation Temperatures and Microstructure of Ti-Ta-Al High Temperature Shape Memory Alloys

Khulief

Mahdy

2022

KEM

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“…Depending on the Ni content, the NiTi alloy can be austenitic or martensitic at room temperature with a range of martensitic start temperature (M s ) ranging from -100°C (52 at.% Ni) to 100°C (51 at.% Ni) [23]. A so-called ''NiTi-like'' alloy containing at least 5 different elements will be expected to be a high entropy and high temperature shape memory alloy [24].…”

Section: Introductionmentioning

confidence: 99%

Investigation and Composition Characterization of a “NiTi-like” Alloy Combining High Temperature Shape Memory and High Entropy

Peltier

Lohmuller

Meraghni

et al. 2020

Shap. Mem. Superelasticity

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New high temperature shape memory alloys with five or more elements are under development and present attractive performances for several functional applications. These active metallic materials are called high entropy and high temperature shape memory alloys (HE-HT-SMAs). This work deals with the characterization of an alloy that combines high temperature shape memory effect and high entropy effect features, a NiCuTiHfZr alloy. The evolution of the phase transformation and the shape memory effect during thermal fatigue was compared with a ternary alloy NiTiZr. Ingots were prepared in a cold crucible and alloys were characterized after thermal cycling at 600 K without a protective gas atmosphere. Optical microscope, X-ray diffraction, and scanning electron microscopy observations showed the presence of martensite in this unpublished alloy at room temperature. The differential scanning calorimetry (DSC) tests showed that martensitic transformation takes place at high temperature. High temperature thermal cycling was performed during a three-point bending tests under constant load without a protective atmosphere. Thermomechanical results showed that high entropy effects increase the operating behavior at high temperature. Hence this new composition of NiCuTiHfZr alloy can be used as an actuator for aerospace and aeronautic application.

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Ti-Ta High Temperature Shape Memory Alloys

Cited by 2 publications

References 9 publications

Effect of Oxidation on the Transformation Temperatures and Microstructure of Ti-Ta-Al High Temperature Shape Memory Alloys

Effect of Oxidation on the Transformation Temperatures and Microstructure of Ti-Ta-Al High Temperature Shape Memory Alloys

Investigation and Composition Characterization of a “NiTi-like” Alloy Combining High Temperature Shape Memory and High Entropy

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