Microstructural Evolution in Ultrafine Grained FeMnSiCr Shape Memory Alloy Modules

2017 ◽  
Vol 1143 ◽  
pp. 214-220 ◽  
Author(s):  
Gheorghe Gurau ◽  
Carmela Gurau ◽  
Mihaela Banu ◽  
Leandru Gheorghe Bujoreanu
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Pressure ◽  
Shape Memory Alloy ◽  
Severe Plastic Deformation ◽  
Shape Memory ◽  
High Speed ◽  
Structural Changes ◽  
High Pressure Torsion ◽  
Transmission Electron

High speed high pressure torsion (HSHPT) processing technology, engineered to achieving (ultra) fine bulk metallic structure under high pressure (~ GPa) and torsion by applying supplementary elevated rotation speed of superior anvil. Coned-disk spring shape modules were processed from an as cast Fe-28Mn-6Si-5Cr (mass %) shape memory alloy (SMA). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed that the structure of modules became submicron as an effect of HSHPT processing. After severe plastic deformation, a grain size gradient was obtained along the truncated cone generator, increasing from inner to outer areas, due to different deformation degrees in these zones. The mechanical and shape memory properties was performed in order to relate the structural changes caused by severe plastic deformation.

scholarly journals Structural Change in Ni-Fe-Ga Magnetic Shape Memory Alloys after Severe Plastic Deformation

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1939 ◽  
Author(s):  
Gheorghe Gurau ◽  
Carmela Gurau ◽  
Felicia Tolea ◽  
Vedamanickam Sampath
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
High Speed ◽  
High Pressure Torsion ◽  
Magnetic Shape Memory ◽  
Two Phase ◽  
Ultrafine Grained

Severe plastic deformation (SPD) is widely considered to be the most efficient process in obtaining ultrafine-grained bulk materials. The aim of this study is to examine the effects of the SPD process on Ni-Fe-Ga ferromagnetic shape memory alloys (FSMA). High-speed high-pressure torsion (HSHPT) was applied in the as-cast state. The exerted key parameters of deformation are described. Microstructural changes, including morphology that were the result of processing, were investigated by optical and scanning electron microscopy. Energy-dispersive X-ray spectroscopy was used to study the two-phase microstructure of the alloys. The influence of deformation on microstructural features, such as martensitic plates, intragranular γ phase precipitates, and grain boundaries’ dependence of the extent of deformation is disclosed by transmission electron microscopy. Moreover, the work brings to light the influence of deformation on the characteristics of martensitic transformation (MT). Vickers hardness measurements were carried out on disks obtained by SPD so as to correlate the hardness with the microstructure. The method represents a feasible alternative to obtain ultrafine-grained bulk Ni-Fe-Ga alloys.

Structure, Thermal Stability and Properties of Grain Boundaries of Submicrocrystalline Mo Obtained by Severe Plastic Deformation

2012 ◽  
Vol 326-328 ◽  
pp. 674-681 ◽  
Author(s):  
Vladimir V. Popov ◽  
Galina P. Grabovetskaya ◽  
A.V. Sergeev ◽  
I.P. Mishin
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Grain Boundaries ◽  
High Pressure Torsion ◽  
Emission Mössbauer Spectroscopy ◽  
Transmission Electron

The structure of submicrocrystalline Mo, obtained by high pressure torsion, its thermal stability and the state of grain boundaries have been studied by transmission electron microscopy and emission Mössbauer spectroscopy.

scholarly journals The Effect of the In-Situ Heat Treatment on the Martensitic Transformation and Specific Properties of the Fe-Mn-Si-Cr Shape Memory Alloys Processed by HSHPT Severe Plastic Deformation

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4621
Author(s):  
Carmela Gurau ◽  
Gheorghe Gurau ◽  
Felicia Tolea ◽  
Bogdan Popescu ◽  
Mihaela Banu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
High Speed ◽  
High Pressure Torsion ◽  
Electron Interaction ◽  
Sudden Increase ◽  
Neel Temperature ◽  
Néel Temperature

This work focuses on the temperature evolution of the martensitic phase ε (hexagonal close packed) induced by the severe plastic deformation via High Speed High Pressure Torsion method in Fe57Mn27Si11Cr5 (at %) alloy. The iron rich alloy crystalline structure, magnetic and transport properties were investigated on samples subjected to room temperature High Speed High Pressure Torsion incorporating 1.86 degree of deformation and also hot-compression. Thermo-resistivity as well as thermomagnetic measurements indicate an antiferromagnetic behavior with the Néel temperature (TN) around 244 K, directly related to the austenitic γ-phase. The sudden increase of the resistivity on cooling below the Néel temperature can be explained by an increased phonon-electron interaction. In-situ magnetic and electric transport measurements up to 900 K are equivalent to thermal treatments and lead to the appearance of the bcc-ferrite-like type phase, to the detriment of the ε(hcp) martensite and the γ (fcc) austenite phases.

scholarly journals Hardness-gradient reversion in FeMnSiCr shape memory alloy modules produced by high-speed high pressure torsion

2015 ◽  
Vol 33 ◽  
pp. 04001 ◽  
Author(s):  
Leandru-Gheorghe Bujoreanu ◽  
Viorel Goanță ◽  
Nicanor Cimpoeșu ◽  
Carmela Gurău ◽  
Marius-Gabriel Suru ◽  
...  
Keyword(s):  
High Pressure ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Speed ◽  
High Pressure Torsion ◽  
Hardness Gradient

Novel High-Speed High Pressure Torsion Technology for Obtaining Fe-Mn-Si-Cr Shape Memory Alloy Active Elements

2014 ◽  
Vol 23 (7) ◽  
pp. 2396-2402 ◽  
Author(s):  
Gheorghe Gurău ◽  
Carmela Gurău ◽  
Octavian Potecaşu ◽  
Petrică Alexandru ◽  
Leandru-Gheorghe Bujoreanu
Keyword(s):  
High Pressure ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Speed ◽  
High Pressure Torsion ◽  
Active Elements

Using High Speed High Pressure Torsion for Cu–13Al–4Ni Shape Memory Alloy Processing

2021 ◽  
Author(s):  
Gheorghe Gurau ◽  
Carmela Gurau ◽  
Francisco Manuel Braz Fernandes ◽  
Rui Jorge Cordeiro Silva ◽  
Florin Marin
Keyword(s):  
High Pressure ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Speed ◽  
High Pressure Torsion

TEM Study of Local Disordering: A Structural Phase Change Induced by High-Pressure Torsion

2008 ◽  
Vol 584-586 ◽  
pp. 422-427 ◽  
Author(s):  
Christian Rentenberger ◽  
Clemens Mangler ◽  
Stephan Scheriau ◽  
Reinhard Pippan ◽  
Hans Peter Karnthaler
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Structural Phase ◽  
Nanocrystalline Structure ◽  
Coarse Grained ◽  
Intermetallic Alloys ◽  
Transmission Electron ◽  
Ordered Intermetallic

Long-range ordered intermetallic alloys with L12 (Ni3Al, Cu3Au) and B2 (FeAl) structures were deformed by high-pressure torsion at room temperature up to high grades of deformation. Transmission electron microscopy shows that disordering caused by the deformation occurs on a very local scale within coarse grains along glide planes (Cu3Au, Ni3Al) and in the form of well defined local regions (Ni3Al, FeAl). The latter leads to a duplex structure consisting of an ordered coarse-grained structure and a disordered nanocrystalline structure. The different mechanisms that can lead to disordering during severe plastic deformation are discussed on the basis of the different ordering energies and on the basis of antiphase boundaries associated with gliding dislocations. The results indicate that in intermetallic alloys the formation of a nanocrystalline structure by severe plastic deformation is facilitated by the loss of order.

Effect of Severe Plastic Deformation on the Structure and Magnetic Behaviour of an Fe-Mn-Si Shape Memory Alloy

2017 ◽  
Vol 1143 ◽  
pp. 240-246 ◽  
Author(s):  
Gheorghe Gurau ◽  
Carmela Gurau ◽  
Felicia Tolea ◽  
Mihaela Valeanu ◽  
Vedamanickam Sampath ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
Magnetic Properties ◽  
Shape Memory Alloy ◽  
Severe Plastic Deformation ◽  
Shape Memory ◽  
Deformation Process ◽  
Magnetic Hysteresis ◽  
Severe Plastic Deformation Process ◽  
Plastic Deformation Process

This work focuses on the relation between severe plastic deformation process via HSHPT and magnetic properties of an Fe–Mn–Si-Cr shape memory alloy. High speed high pressure torsion (HSHPT) was applied on cast state of alloy. Microstructure evolution of severe plastic deformed iron based alloy subjected to different deformation degree were investigated. The microstructure and phase compositions of alloy were characterized using optical microscopy, scanning electron microscopy and transmission electron microscopy. The magnetic properties are discussed on the basis of the severe plastic deformation process and the underlying martensitic transformation. Thermomagnetic curves, between 150 K and 390 K and magnetic hysteresis loops at 300 K temperatures were measured. The thermo-resistivity measurements were done by standard four-probe. The magnetic properties are interpreted and correlated with microstructure.

Evaluation of the Mechanical Properties of Glass/Epoxy Composite by Embedding Shape Memory Alloy and Nanoclay

2021 ◽  
Vol 1019 ◽  
pp. 3-11
Author(s):  
Niranjan Pattar ◽  
S.F. Patil ◽  
Pratik Patil ◽  
Iranna Anikivi ◽  
Shridhar Hiremath
Keyword(s):  
Electron Microscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Smart Materials ◽  
Epoxy Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Clay Concentration ◽  
Impact Characteristics

Embedding smart materials in the composite to enhance mechanical strength have become a research hotspot owing to their unique properties. The present research also focus on novel way to fabricate composite by embedding Shape Memory Alloy (SMA) wire and montmorillonite (MMT) nanoclay by varying clay concentration (0-7 wt.%). The extent of dispersion of nanoclay in epoxy resin was studied using Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD). Fabricated samples were examined for tensile, flexural and impact characteristics. Scanning Electron Microscopy (SEM) was used to study the adhesion, delamination and damage occurred within the composite due to tensile loading. Results shows that the tensile strength, flexural strength and impact energy of SMA/MMT/glass/epoxy composite was improved by 23%, 21% and 57% respectively, when it was compared with composite with glass/epoxy composite.

Sign in / Sign up

Export Citation Format

Share Document