Thermomechanical processing effects on the structure and properties of Fe-based SMAs. I. Evolution of phase structure

Bulbuc, V.; Pricop, Bogdan; Popa, Mihai; Mihalache, Elena; Özkal, Burak; Bujoreanu, Leandru-Gheorghe

doi:10.1088/1757-899x/485/1/012004

Cited by 2 publications

(4 citation statements)

References 11 publications

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“…With regard to the FeMnSi-2Cu sample, the thermogram in Figure 3 b shows a reduction in the elastic modulus in the temperature domain of 50–60 °C and is associated with the specific solid-state transformations of this alloy [ 55 , 56 ].…”

Section: Resultsmentioning

confidence: 99%

“…austenite, and two internal friction maxima (tanδ) associated with succeeding recoveries to austenite γ (fcc) of martensite α′-bcc and ε-hcp, respectively [54]. With regard to the FeMnSi-2Cu sample, the thermogram in Figure 3b shows a reduction in the elastic modulus in the temperature domain of 50-60 °C and is associated with the specific solid-state transformations of this alloy [55,56].…”

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 98%

“…AFM results of measured martensite plates (average of 5 determinations on 5 plates for each sample), before and after DMA testing, for FeMnSi-1.5Cu and FeMnSi-2Cu samples. With regard to the FeMnSi-2Cu sample, the thermogram in Figure 3b shows a reduction in the elastic modulus in the temperature domain of 50-60 • C and is associated with the specific solid-state transformations of this alloy [55,56].…”

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 99%

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Investigations on the Degradation Behavior of Processed FeMnSi-xCu Shape Memory Alloys

Roman,

Cimpoeșu,

Pricop

et al. 2024

Nanomaterials

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A new functional Fe-30Mn-5Si-xCu (x = 1.5 and 2 wt%) biomaterial was obtained from the levitation induction melting process and evaluated as a biodegradable material. The degradation characteristics were assessed in vitro using immersion tests in simulated body fluid (SBF) at 37 ± 1 °C, evaluating mass loss, pH variation that occurred in the solution, open circuit potential (OCP), linear and cyclic potentiometry (LP and CP), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and nano-FTIR. To obtain plates as samples, the cast materials were thermo-mechanically processed by hot rolling. Dynamic mechanical analysis (DMA) was employed to evaluate the thermal properties of the smart material. Atomic force microscopy (AFM) was used to show the nanometric and microstructural changes during the hot rolling process and DMA solicitations. The type of corrosion identified was generalized corrosion, and over the first 3–5 days, an increase in mass was observed, caused by the compounds formed at the metal–solution interface. The formed compounds were identified mainly as oxides that passed into the immersion liquid. The degradation rate (DR) was obtained as a function of mass loss, sample surface area and immersion duration. The dynamic mechanical behavior and dimensions of the sample were evaluated after 14 days of immersion. The nanocompounds found on the surface after atmospheric corrosion and immersion in SBF were investigated with the Neaspec system using the nano-FTIR technique.

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Section: Resultsmentioning

confidence: 99%

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 98%

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 99%

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Investigations on the Degradation Behavior of Processed FeMnSi-xCu Shape Memory Alloys

Roman,

Cimpoeșu,

Pricop

et al. 2024

Nanomaterials

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“…It was also noticed that martensite plate variants became more diversified with the increase of MA fraction and more complexly intersected, as more γ-fcc austenite transformed to α -bcc and ε-hcp stress-induced martensites (Bulbuc et al, 2019).…”

Section: Thermomechanical Processing and Pre-straining Effectsmentioning

confidence: 98%

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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Thermomechanical processing effects on the structure and properties of Fe-based SMAs. I. Evolution of phase structure

Cited by 2 publications

References 11 publications

Investigations on the Degradation Behavior of Processed FeMnSi-xCu Shape Memory Alloys

Investigations on the Degradation Behavior of Processed FeMnSi-xCu Shape Memory Alloys

Powder Metallurgy: An Alternative for FeMnSiCrNi Shape Memory Alloys Processing

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