Effect of Phase Changes on the Axial Modulus of an FeMnSi-Shape Memory Alloy.

Yajiao Yang,Moslem Shahverdi,Matteo Breveglieri

doi:10.3390/ma14174815

Abstract

The axial modulus ESMA(κ) of FeMnSi-based shape memory alloys (FeMnSi-SMAs) is a parameter introduced in this study to characterize the relationship between stress and strain behavior at the early stage of tensile loading. ESMA(κ) can be used to correctly estimate and model the interaction forces between FeMnSi-SMAs and other materials. Unlike the conventional Young’s modulus, which is usually given at room temperature, the ESMA(κ) is evaluated at different temperatures and strongly depends on phase transformation and plastic deformation. This study investigated the evolution of ESMA(κ) during and after pre-straining as well as in the course of the activation processes. The effect of different factors (e.g., phase transformation and plastic deformation) on the magnitude of ESMA(κ) is discussed. The result shows that the ESMA(κ) can differ significantly during activation and thus needs to be modified when interaction forces between FeMnSi-SMAs and other substrates materials (e.g., concrete) must be modeled and evaluated.

Highlights

Materials 2021, 14, 4815. https://Shape memory alloys (SMAs) are unique alloys that can recover their shapes caused by deformation through unloading or upon heating above a specific temperature
Because of the shape memory effect (SME) and superelasticity, SMAs are widely applied in the automotive, aerospace, robotic, civil engineering, and biomedical domains [1,2,3,4,5,6,7,8,9]
The specimens consist of FeMnSi-SMA strips, which were laser-cut into a final geometry equal to 250 mm of length, a width of 15 mm, and a thickness of 1.5 mm

Summary

Introduction

Materials 2021, 14, 4815. https://Shape memory alloys (SMAs) are unique alloys that can recover their shapes caused by deformation through unloading or upon heating above a specific temperature. Because of the shape memory effect (SME) and superelasticity, SMAs are widely applied in the automotive, aerospace, robotic, civil engineering, and biomedical domains [1,2,3,4,5,6,7,8,9]. NiTibased SMAs (NiTi-SMAs) have played a leading role in the industry owing to their good. They are high-priced, implying that they cannot be employed in large amounts as required in civil engineering. As an alternative to NiTi-SMAs, the FeMnSibased SMA (FeMnSi-SMA) has attracted considerable attention over the past two decades due to its low cost, good machinability, workability, and weldability [10]. A big advantage of an iron-based SMA is the significantly higher Young’s modulus in comparison to NiTi-based products [11]

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