scholarly journals Martensitic transformation behavior and structural characteristics of annealed Ni-Mn-Sn-Fe-In Heusler alloy

2021 ◽  
Vol 2070 (1) ◽  
pp. 012231
Author(s):  
S. Nambiar Sandeep ◽  
B.R.N. Murthy ◽  
Sharma Sathyashankara ◽  
A. A. Prasanna
Keyword(s):  
Martensitic Transformation ◽  
Heusler Alloy ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fine Grain ◽  
Energy Dispersion Spectrometry ◽  
Testing Facility

Abstract Ni-Mn based heusler alloy with Ni50-xFexMn30Sn20-yIny where 1<=x<=4; 2<=y<=8 are studied for their structural as well as mechanical characteristics using various testing facility such as field emission scanning electron microscope, energy dispersion spectrometry, differential scanning calorimetry and Vickers hardness equipment. From the general understanding the materials are to display a transformation of austenite-martensite. The materials are seen to be showing this transformation in and around near room temperature. The optical and FESEM imaging of the specimen show that during annealing heating to high temperature to longer time, the diffusion kinetics are activated at faster rate so that the dendritically structure is annihilated to develop well distributed grain structure. The coarser dendrites seems to be broken and fine grain, well dispersed phases are formed. X-ray diffraction confirms the peak split and martensitic transformation in the system of alloys. DSC results confirm the martensitic transformation around room temperature.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

Influence of Gd Addition on the Structure and Capability of Ni-Mn-In Metamagnetic Shape Memory Alloys

2012 ◽  
Vol 535-537 ◽  
pp. 950-953
Author(s):  
Li Na Bai ◽  
Gui Xing Zheng ◽  
Zhi Jian Duan ◽  
Jian Jun Zhang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Transition Temperature ◽  
Martensitic Transformation ◽  
Room Temperature ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The influences of Gd concentration on martensitic transformation and magnetic properties of NiMnIn alloys were investigated by differential scanning calorimetry (DSC) , vibrating sample magnetometry (VSM), X-ray diffraction (XRD) and etc. It is Observed through the experiment: the addition of Gd enhances martensite transition temperature;X-ray diffraction analysis of experimental alloys is revealed that to the mixture is martensite and austenite at room temperature; content of Gd is not proportional to the improvement of magnetic property.

scholarly journals Martensitic Transformation and Crystalline Structure of Ni50Mn50−xSnx Melt-Spun Heusler Alloys

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 853
Author(s):  
Rim Ameur ◽  
Mahmoud Chemingui ◽  
Tarek Bachaga ◽  
Lluisa Escoda ◽  
Mohamed Khitouni ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Room Temperature ◽  
Solidification Rate ◽  
Heusler Alloys ◽  
X Ray Diffraction ◽  
Key Factors ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Characteristic Temperatures ◽  
Melt Spun

The structure and thermal behavior are key factors that influence the functional response of Ni–Mn–Sn alloys. The present study reports the production as well as the structure and thermal analysis of melt-spun (solidification rate: 40 ms−1) Ni50 Mn50−xSnx (x = 10, 11, 12 and 13 at.%) alloys. X-ray diffraction measurements were performed at room temperature. The austenite state has an L21 structure, whereas the structure of the martensite is 7M or 10M (depending on the Sn/Mn percentage). Furthermore, the structural martensitic transformation was detected by differential scanning calorimetry (DSC). As expected, upon increasing the Sn content, the characteristic temperatures also increase. The same tendency is detected in the thermodynamic parameters (entropy and enthalpy). The e/a control allows the development production of alloys with a transformation close to room temperature.

scholarly journals Effect of Al Addition on Martensitic Transformation Stability and Microstructural and Mechanical Properties of CuZr Based Shape Memory Alloys

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1141
Author(s):  
Carlo Alberto Biffi ◽  
Jacopo Fiocchi ◽  
Mauro Coduri ◽  
Ausonio Tuissi
Keyword(s):  
Mechanical Properties ◽  
Martensitic Transformation ◽  
Binary Alloy ◽  
Room Temperature ◽  
Secondary Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Al Content ◽  
Compressive Response ◽  
Al Addition

In this work, the effect of the Al content (x = 5, 10, and 15 at. %) on the martensitic transformation (MT) and microstructure and mechanical properties of Cu(50−x)Zr50Alx alloys was studied. The microstructure of the alloys was characterized at room temperature by means of scanning electron microscopy and X-ray diffraction. An increase in Al content reduces the amount of transforming CuZr phase, and consequently the secondary phase formation is favored. The evolution of the MT upon thermal cycling was investigated as a function of the Al content by differential scanning calorimetry. MT temperatures and enthalpies were found to be decreased when increasing the Al content. Al addition can induce a sudden, stable MT below 0 °C, while the binary alloy requires ten complete thermal cycles to stabilize. Finally, the mechanical properties were investigated through microhardness and compression testing. No linear dependence was found with composition. Hardness lowering effect was observed for 5–10 at. % of Al content, while the hardness was increased only for 15 at. % Al addition with respect to the binary alloy. Similarly, compressive response of the alloys showed behavior dependent on the Al content. Up to 10 at. % Al addition, the alloys indicate a superelastic response at room temperature, while higher Al content induced untimely failure.

Ionic Conductivities of Doped CeO2 Thin Films as Related to Their Microstructure

1995 ◽  
Vol 411 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Ionic Conductivities ◽  
Dielectric Constants ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Fine Grain ◽  
Brick Layer Model ◽  
Columnar Grain ◽  
Beam Deposition

ABSTRACTThin films of 4% Y2O3 doped CeO2/Pd film/(001)LaA103 with a very low pinhole density were successfully prepared using electron-beam deposition technique. The microstructure of the films was characterized by x-ray diffraction and the electrical properties were studied as a function of temperature with AC impedance spectroscopy. A brick layer model was adopted to correlate the electrical properties to the microstructure of the films, which can be simplified as either a series or a parallel equivalent circuit associated with either a fine grain or a columnar grain structure, respectively. The conductivities of the films fell between the conductivities derived from the two circuit models, suggesting that the films are of a mixed fine grain and columnar grain structure. The measured dielectric constants of the films were found smaller than that of the bulk.

Room Temperature Screw Form Rolling of AZ91D Magnesium Alloy through Processing by Extrusion-Torsion Simultaneous Working

2014 ◽  
Vol 783-786 ◽  
pp. 375-379
Author(s):  
Mitsuaki Furui ◽  
Shouyou Sakashita ◽  
Kazuya Shimojima ◽  
Tetsuo Aida ◽  
Kiyoshi Terayama ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Hardness Measurement ◽  
Rolling Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Az91d Magnesium Alloy ◽  
Microstructure Observation ◽  
Fine Grain ◽  
Simultaneous Processing

Extrusion-torsion simultaneous processing is a very attractive technique for fabricating a rod-shape material with fine grain and random texture. We have proposed a new screw form rolling process combined with preliminary extrusion-torsion simultaneous working. Microstructure evolution and mechanical property change of AZ91D magnesium alloy during extrusion-torsion simultaneous processing was examined through microstructure observation, X-ray diffraction analysis and micro-Vickers hardness measurement. By the addition of torsion, the crystal orientation of AZ91D magnesium alloy workpiece was drastically changed from basal crystalline orientation to the random orientation. Crystal grain occurred through the dynamic recrystallization and tended to coarsen with an increase of extrusion-torsion temperature. Grain refinement under 2 um was achieved at the lowest extrusion-torsion temperature of 523 K. M8 gauge AZ91D magnesium alloy screw was successfully formed at room temperature using the extrusion-twisted workpiece preliminary solution treating at 678 K for 345.6 ks. It was found that the extrusion-torsion temperature of 678 K must be selected to fabricate the good screw without any defects.

scholarly journals Viability of the microencapsulation of a casein hydrolysate in lipid microparticles of cupuacu butter and stearic acid

2013 ◽  
Vol 2 (1) ◽  
Author(s):  
Samantha Cristina Pinho ◽  
Janaina Costa Da Silva
Keyword(s):  
Stearic Acid ◽  
Room Temperature ◽  
Casein Hydrolysate ◽  
Polysorbate 80 ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Initial Amount ◽  
X Ray ◽  
Lipid Mixtures ◽  
Lipid Microparticles

Solid lipid microparticles produced with a mixture of cupuacu butter and stearic acid were used to microencapsulate a commercial casein hydrolysate (Hyprol 8052). The composition of the lipid matrix used for the production of the lipid microparticles was chosen according to data on the wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) of bulk lipid mixtures, which indicated that the presence of 10 % cupuacu butter was sufficient to significantly change the crystalline arrangement of pure stearic acid. Preliminary tests indicated that a minimum proportion of 4 % of surfactant (polysorbate 80) was necessary to produce empty spherical lipid particles with average diameters below 10 mm. The lipid microparticles were produced using 20 % cupuacu butter and 80 % stearic acid and then stabilized with 4 % of polysorbate 80, exhibiting an encapsulation efficiency of approximately 74 % of the casein hydrolysate. The melting temperature of the casein hydrolysate-loaded lipid microparticles was detected at 65.2 °C, demonstrating that the particles were solid at room temperature as expected and indicating that the incorporation of peptides had not affected their thermal behavior. After 25 days of storage, however, there was a release of approximately 30 % of the initial amount of encapsulated casein hydrolysate. This release was not thought to have been caused by the liberation of encapsulated casein hydrolysate. Instead, it was attributed to the possible desorption of the adsorbed peptides present on the surface of the lipid microparticles.

Study of thermal properties of Ga0.5In1.5Se3 by differential scanning calorimetry

2021 ◽  
pp. 2150407
Author(s):  
S. I. Ibrahimova
Keyword(s):  
Crystal Structure ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Thermal Effects ◽  
Room Temperature ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
Scanning Calorimetry ◽  
X Ray

The crystal structure and thermal properties of the [Formula: see text] compound have been investigated. Structural studies were performed by X-ray diffraction at room temperature. The crystal structure of this compound was found to correspond to the hexagonal symmetry of the space group P61. Thermal properties were studied using a differential scanning calorimetry (DSC). It was found in the temperature range [Formula: see text] that thermal effects occur at temperatures [Formula: see text] and [Formula: see text]. The thermodynamic parameters of these effects are calculated.

The structures and phase transitions in 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2]

2019 ◽  
Vol 75 (6) ◽  
pp. 1144-1151
Author(s):  
Tamara J. Bednarchuk ◽  
Wolfgang Hornfeck ◽  
Vasyl Kinzhybalo ◽  
Zhengyang Zhou ◽  
Michal Dušek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Room Temperature ◽  
Variable Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Space Group ◽  
X Ray

The organic–inorganic hybrid compound 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2] (4apFeS), was obtained by slow evaporation of the solvent at room temperature and characterized by single-crystal X-ray diffraction in the temperature range from 290 to 80 K. Differential scanning calorimetry revealed that the title compound undergoes a sequence of three reversible phase transitions, which has been verified by variable-temperature X-ray diffraction analysis during cooling–heating cycles over the temperature ranges 290–100–290 K. In the room-temperature phase (I), space group C2/c, oxygen atoms from the closest Fe-atom environment (octahedral) were disordered over two equivalent positions around a twofold axis. Two intermediate phases (II), (III) were solved and refined as incommensurately modulated structures, employing the superspace formalism applied to single-crystal X-ray diffraction data. Both structures can be described in the (3+1)-dimensional monoclinic X2/c(α,0,γ)0s superspace group (where X is ½, ½, 0, ½) with modulation wavevectors q = (0.2943, 0, 0.5640) and q = (0.3366, 0, 0.5544) for phases (II) and (III), respectively. The completely ordered low-temperature phase (IV) was refined with the twinning model in the triclinic P{\overline 1} space group, revealing the existence of two domains. The dynamics of the disordered anionic substructure in the 4apFeS crystal seems to play an essential role in the phase transition mechanisms. The discrete organic moieties were found to be fully ordered even at room temperature.

scholarly journals Dielectric properties and conductivity of PVdF-co-HFP/LiClO4 polymer electrolytes

2018 ◽  
Vol 96 (7) ◽  
pp. 786-791 ◽  
Author(s):  
Kemal Ulutaş ◽  
Ugur Yahsi ◽  
Hüseyin Deligöz ◽  
Cumali Tav ◽  
Serpil Yılmaztürk ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Polymer Electrolytes ◽  
Room Temperature ◽  
Solid Polymer Electrolytes ◽  
Solid Polymer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Maximum Conductivity

In this study, it was aimed to prepare a series of PVdF-co-HFP based electrolytes with different LiClO4 loadings and to investigate their chemical and electrical properties in detail. For this purpose, PVdF-co-HFP based electrolytes with different LiClO4 loadings (1–20 weight %) were prepared using solution casting method. X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric (TGA) –differential thermal and dielectric spectroscopy analysis of PVdF-co-HFP/LiClO4 were performed to characterize their structural, thermal, and dielectric properties, respectively. XRD results showed that the diffraction peaks of PVdF-co-HFP/LiClO4 electrolytes broadened and decreased with LiClO4. TGA patterns exhibited that PVdF-co-HFP/LiClO4 electrolytes with 20 wt % of LiClO4 had the lowest thermal stability and it degraded above 473 K, which is highly applicable for solid polymer electrolytes. Dielectric constant, dielectric loss, and conductivities were calculated by measuring capacitance and dielectric loss factor of PVdF-co-HFP/LiClO4 in the range from 10 mHz to 20 MHz frequencies at room temperature. In consequence, conductivities of PVdF-co-HFP/LiClO4 increased significantly with frequency for low loading of LiClO4 while they only slightly changed with higher LiClO4 addition. On the other hand, dielectric constant values of PVdF-co-HFP/LiClO4 films decreased with frequency whereas they rose with LiClO4 addition. The dielectric studies showed an increase in dielectric constant and dielectric loss with decreasing frequency. This result was attributed to high contribution of charge accumulation at the electrode–electrolyte interface. The electrolyte showed the maximum conductivity of 8 × 10−2 S/cm at room temperature.

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