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On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs

A sudden increase in storage modulus (ΔE′) was repeatedly recorded during the heating of powder metallurgy (PM) 66Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloy specimens subjected to dynamic mechanical analysis (DMA), under constant applied strain amplitude and frequency. This instability, exceed...

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Autores principales: Pricop, Bogdan, Grigoraș, Marian, Borza, Firuța, Özkal, Burak, Bujoreanu, Leandru-Gheorghe
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9324162/
https://www.ncbi.nlm.nih.gov/pubmed/35889567
http://dx.doi.org/10.3390/nano12142342
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author Pricop, Bogdan
Grigoraș, Marian
Borza, Firuța
Özkal, Burak
Bujoreanu, Leandru-Gheorghe
author_facet Pricop, Bogdan
Grigoraș, Marian
Borza, Firuța
Özkal, Burak
Bujoreanu, Leandru-Gheorghe
author_sort Pricop, Bogdan
collection PubMed
description A sudden increase in storage modulus (ΔE′) was repeatedly recorded during the heating of powder metallurgy (PM) 66Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloy specimens subjected to dynamic mechanical analysis (DMA), under constant applied strain amplitude and frequency. This instability, exceeding 12 GPa, was associated with the reverse martensitic transformation of α′-body centered cubic (bcc) martensite to γ-face centered cubic (fcc) austenite, overlapped on a magnetic transition. This transition, observed by thermomagnetic measurements (T-MAG), was associated with the temporary spontaneous alignment of magnetic spins, which lasted until thermal movement became prevalent, during heating. ΔE′ was located around 250 °C on DMA thermograms and this temperature had the tendency to increase with the solution treatment temperature. On T-MAG diagrams, magnetization saturation temperature decreased from 405 °C to 52 °C with the increase in applied magnetic field from 20 Oe to 1 kOe and the increase in mechanically alloyed powder volume from 20% to 40%. On scanning electron micrographs, the presence of thermally induced α’-bcc martensite was emphasized together with the sub-bands that impede its stress-induced formation during DMA solicitation. On X-ray diffraction patterns of the solution-treated specimens, the presence of 22–82% α′-bcc martensite was identified, together with 8–55% retained austenite. It was assumed that the pre-existence of austenite together with α’-bcc martensite, in the microstructure of the solution-treated specimens, favored the magnetic transition, which destabilized the material and caused the storage modulus increase. The specimen comprising the largest amounts of austenite experienced the largest ΔE′.
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spelling pubmed-93241622022-07-27 On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs Pricop, Bogdan Grigoraș, Marian Borza, Firuța Özkal, Burak Bujoreanu, Leandru-Gheorghe Nanomaterials (Basel) Article A sudden increase in storage modulus (ΔE′) was repeatedly recorded during the heating of powder metallurgy (PM) 66Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloy specimens subjected to dynamic mechanical analysis (DMA), under constant applied strain amplitude and frequency. This instability, exceeding 12 GPa, was associated with the reverse martensitic transformation of α′-body centered cubic (bcc) martensite to γ-face centered cubic (fcc) austenite, overlapped on a magnetic transition. This transition, observed by thermomagnetic measurements (T-MAG), was associated with the temporary spontaneous alignment of magnetic spins, which lasted until thermal movement became prevalent, during heating. ΔE′ was located around 250 °C on DMA thermograms and this temperature had the tendency to increase with the solution treatment temperature. On T-MAG diagrams, magnetization saturation temperature decreased from 405 °C to 52 °C with the increase in applied magnetic field from 20 Oe to 1 kOe and the increase in mechanically alloyed powder volume from 20% to 40%. On scanning electron micrographs, the presence of thermally induced α’-bcc martensite was emphasized together with the sub-bands that impede its stress-induced formation during DMA solicitation. On X-ray diffraction patterns of the solution-treated specimens, the presence of 22–82% α′-bcc martensite was identified, together with 8–55% retained austenite. It was assumed that the pre-existence of austenite together with α’-bcc martensite, in the microstructure of the solution-treated specimens, favored the magnetic transition, which destabilized the material and caused the storage modulus increase. The specimen comprising the largest amounts of austenite experienced the largest ΔE′. MDPI 2022-07-08 /pmc/articles/PMC9324162/ /pubmed/35889567 http://dx.doi.org/10.3390/nano12142342 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Pricop, Bogdan
Grigoraș, Marian
Borza, Firuța
Özkal, Burak
Bujoreanu, Leandru-Gheorghe
On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs
title On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs
title_full On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs
title_fullStr On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs
title_full_unstemmed On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs
title_short On the Possible Cause of Sudden Storage Modulus Increase during the Heating of PM FeMnSiCrNi SMAs
title_sort on the possible cause of sudden storage modulus increase during the heating of pm femnsicrni smas
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9324162/
https://www.ncbi.nlm.nih.gov/pubmed/35889567
http://dx.doi.org/10.3390/nano12142342
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