Factors influencing martensite transitions in Fe-based shape memory alloys

Mihalache, Elena; Pricop, Bogdan; Suru, Marius-Gabriel; Lohan, Nicoleta Monica; Comaneci, Radu; Istrate, Bogdan; Özkal, Burak; Bujoreanu, Leandru-Gheorghe

doi:10.1051/matecconf/20153304002

Cited by 10 publications

(5 citation statements)

References 35 publications

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“…On the other hand, the present authors pointed out that, in MA'ed Fe–Mn–Si–Cr–Ni SMAs, a second internal friction maximum occurs during heating. This tan δ maximum, located at a temperature (a temperature where 50% of antiferromagnetic martensite transformed to paramagnetic martensite), was associated with antiferromagnetic-paramagnetic transition characterised by Néel temperature ( T N ) [16].…”

Section: Methodsmentioning

confidence: 99%

“…One peculiarity of PM FeMnSi-based SMAs is the formation of large amounts of α ′ -bcc thermally induced martensite [15]. The presence of α ′ was associated with large levels of internal friction [16] which experienced an increasing trend together with the pre-straining degree and the MA'ed fraction [17]. The amount of α ′ increased additionally with the number of mechanical cycles [18], the volume fraction of MA'ed powder [19] and pre-straining degree, except for the specimens ST'ed at 1273 and 1373 K [20].…”

Section: Introductionmentioning

confidence: 99%

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Thermo-mechanical effects caused by martensite formation in powder metallurgy FeMnSiCrNi shape memory alloys

et al. 2018

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The paper reports solution treatment (ST) and mechanical alloying (MA) effects on the structure and static/dynamic mechanical behaviour of PM-MA'ed FeMnSiCrNi shape memory alloys associated with the formation of thermally and stress-induced martensite. The specimens were subjected to tensile pre-straining, in order to stress induce martensite and their gauges were cut and prepared for X-ray diffraction (XRD) as well as for optical and scanning electron microscopy (SEM). XRD patterns allowed determining the presence of large amounts of α ′ -body centred cubic (bcc) besides ε-hexagonal close packed (hcp) martensite and γ-face centred cubic (fcc) austenite. The decrease in the amount of α ′ -bcc at specimens ST'ed at 1273 and 1373 K, with increasing pre-straining degree, was confirmed by XRD patterns and SEM micrographs. Dynamic mechanical analysis (DMA) was performed by strain sweeps (SS). The SS-DMA graphs displayed storage modulus plateaux which were associated with the formation of ε-hcp martensite.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermo-mechanical effects caused by martensite formation in powder metallurgy FeMnSiCrNi shape memory alloys

et al. 2018

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“…The formation of thermally induced α -bcc martensite was revealed, as a particularity of these P/M-MA'ed alloys. Martensite plates became finer with the increase of MA'ed fraction, which enhanced a global increasing tendency of the amount of α -bcc martensite on behalf of the amount of γ-fcc austenite (Mihalache et al, 2015). It has been concluded that internal friction, determined statically and dynamically, experienced an increasing trend with prestraining degree, heat treatment temperature and MA'ed fraction (Mihalache et al, 2017).…”

Section: Thermomechanical Processing and Pre-straining Effectsmentioning

confidence: 96%

Powder Metallurgy: An Alternative for FeMnSiCrNi Shape Memory Alloys Processing

et al. 2020

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In the case of quintenary Fe-Mn-Si-Cr-Ni shape memory alloys (SMAs), ingot metallurgy (IM) has technological shortcomings concerning compositional segregation, imperfect melt-incorporation of Si, demanganization during heating and cooling-induced cracking, which can be effectively surmounted by combining powder metallurgy (PM) with mechanical alloying (MA). The paper reviews the results reported in the processing and characterization of PM-MA'ed FeMnSiCrNi SMAs, with special emphasis on the findings obtained by present authors in the last decade. Specimens with nominal chemical compositions Fe-18Mn-3Si-7Cr-4Ni and Fe-14Mn-6Si-9Cr-5Ni (mass %) were produced by IM and PM. In the latter case various volume fractions of as-blended powders were MA'ed under protective atmosphere, before being pressed and sintered. Further compacting, up to 5% porosity degrees, was achieved by hot rolling. Structural analysis, performed by X-ray diffraction and scanning electron microscopy, revealed the formation of unusually large amounts of α-body centred cubic (bcc) thermally induced martensite. This undesirable martensite seemed to be destabilized by tensile pre-straining, and enabled PM specimens to reach higher stresses than IM ones. The formation and accumulation of α-bcc stress induced martensite was enhanced by tensile pre-straining, mechanical cycling and augmentation of MA'ed powder fraction. It has been argued that the optimization of technological processing parameters of heat treatment (HT) and hot rolling (HR) combined with MA'ed powder fraction caused the augmentation of shape memory effect (SME) magnitude. DMA-temperature scans revealed an increasing tendency of internal friction (tan δ) with MA'ed powder fraction, as well as the presence of two tan δ maxima ascribed to antiferromagneticparamagnetic transition and martensite reversion to austenite, respectively. DMA-strain sweeps emphasized the occurrence of a plateau on the storage modulus vs. strain amplitude variation which was associated with stress-induced formation of ε hexagonal close-packed (hcp)-martensite. In spite of large α-bcc amounts, PM-MA'ed Fe-14Mn-6Si-9Cr-5Ni experienced free-recovery SME which was enhanced by thermomechanical training. Coupling rings, meant to connect vibrating pipes that transport turbulent fluids, being able to mitigate vibrations that could accidentally open the connection, were manufactured and tested.

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“…When Fe-SMA is employed as a measure of prestressing, the amount of prestress is the property of most concern to engineers. With the aim of increasing the shape recovery properties, many research groups across the world have been devoted to developing improved production and manufacturing processes, including but not limited to thermal mechanical training, adjusting the chemical compositions and heat treatment [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ]. These efforts greatly enhance the reliability of Fe-SMA as an emerging prestressing strategy.…”

Section: Basic Propertiesmentioning

confidence: 99%

Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

Zhang

et al. 2022

Materials

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As a promising candidate in the construction industry, iron-based shape memory alloy (Fe-SMA) has attracted lots of attention in the engineering and metallography communities because of its foreseeable benefits including corrosion resistance, shape recovery capability, excellent plastic deformability, and outstanding fatigue resistance. Pilot applications have proved the feasibility of Fe-SMA as a highly efficient functional material in the construction sector. This paper provides a review of recent developments in research and design practice related to Fe-SMA. The basic mechanical properties are presented and compared with conventional structural steel, and some necessary explanations are given on the metallographic transformation mechanism. Newly emerged applications, such as Fe-SMA-based prestressing/strengthening techniques and seismic-resistant components/devices, are discussed. It is believed that Fe-SMA offers a wide range of applications in the construction industry but there still remains problems to be addressed and areas to be further explored. Some research needs at material-level, component-level, and system-level are highlighted in this paper. With the systematic information provided, this paper not only benefits professionals and researchers who have been working in this area for a long time and wanting to gain an in-depth understanding of the state-of-the-art, but also helps enlighten a wider audience intending to get acquainted with this exciting topic.

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Factors influencing martensite transitions in Fe-based shape memory alloys

Cited by 10 publications

References 35 publications

Thermo-mechanical effects caused by martensite formation in powder metallurgy FeMnSiCrNi shape memory alloys

Thermo-mechanical effects caused by martensite formation in powder metallurgy FeMnSiCrNi shape memory alloys

Powder Metallurgy: An Alternative for FeMnSiCrNi Shape Memory Alloys Processing

Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

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