scholarly journals Structural configuration and tetragonal phase stability in the equiatomic quaternary Heusler compound TiZnMnSi

RSC Advances ◽  
2020 ◽  
Vol 10 (65) ◽  
pp. 39731-39738
Author(s):  
Jiaying Ji ◽  
Qijia Gu ◽  
Rabah Khenata ◽  
Fayang Guo ◽  
Yanfeng Wang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Stability ◽  
Tetragonal Phase ◽  
Strong Tendency ◽  
Structural Configuration ◽  
Heusler Compound ◽  
Quaternary Heusler Compound

The equiatomic quaternary Heusler compound TiZnMnSi exhibits strong tendency to tetragonal phase transformation.

scholarly journals Theoretical Study of the Electronic and Magnetic Properties and Phase Stability of the Full Heusler Compound Pd2CoAl

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 422 ◽  
Author(s):  
Liyu Hao ◽  
Jiaxue You ◽  
Rabah Khenata ◽  
Yanfeng Wang ◽  
Xiaotian Wang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Total Energy ◽  
Density Of States ◽  
Magnetic Moment ◽  
Tetragonal Phase ◽  
Total Magnetic Moment ◽  
First Principles Calculation ◽  
Tetragonal Structure ◽  
Heusler Compound ◽  
Full Heusler

Based on first principles calculation, a systematical investigation has been performed to study the electronic, magnetic, dynamic, and mechanical properties of the full Heusler compound Pd2CoAl. It is found that the L21-type structure is energetically more stable than the XA-type due to the lower total energy. The obtained lattice constant in cubic ground state is 6.057 Å, which matches well with previous study. The calculated electronic band structure reveals the metallic nature of Pd2CoAl and its total magnetic moment of 1.78 μB is mainly contributed by Co atom from strong spin splitting effect, as indicated with the distinctive distributions of the density of states in two spin directions. Under uniform strains from −5% to +5%, the variation of total magnetic moment has been obtained and it is still caused by the much larger change from Co atom, compared with Pd and Al atoms. The tetragonal structure has further been analyzed and we found that there is possible martensitic phase transformation because the total energy can be further reduced when the cubic structure is varied into the tetragonal one. The large energy difference of 0.165 eV between the tetragonal and cubic phases is found at the c/a ratio of 1.30. The total density of states has been compared between the cubic and tetragonal phases for Pd2CoAl and results show tetragonal phase transformation could reduce the states at the Fermi energy level in both directions. In addition, the dynamic and mechanical stabilities have also been evaluated for Pd2CoAl in both cubic and tetragonal structures and results confirm that the tetragonal phase shows good stability against the cubic phase, which further verifies that the tetragonal phase transformation is highly expected. In the end, the strong elastic anisotropy in the tetragonal structure has been clearly shown with the calculated directional dependence of the Young’s modulus and shear modulus.

Ferroelectric Domain Structure of Pb(Zr.52Ti.48)03

1980 ◽  
Vol 38 ◽  
pp. 214-215
Author(s):  
E.K. Goo ◽  
R.K. Mishra
Keyword(s):  
Phase Transformation ◽  
Domain Structure ◽  
Tetragonal Phase ◽  
Ferroelectric Domain ◽  
Cubic Phase ◽  
Ion Milling ◽  
Thin Foils ◽  
Ferroelectric Domain Structure ◽  
Ferroelectric Domains

Ferroelectric domains are twins that are formed when PZT undergoes a phase transformation from a non-ferroelectric cubic phase to a ferroelectric tetragonal phase upon cooling below ∼375°C.,1 The tetragonal phase is spontaneously polarized in the direction of c-axis, making each twin a ferroelectric domain. Thin foils of polycrystalline Pb (Zr.52Ti.48)03 were made by ion milling and observed in the Philips EM301 with a double tilt stage.

Phase transformation and preferred orientation in carboxylate derived ZrO2 thin films on silicon substates

1992 ◽  
Vol 7 (11) ◽  
pp. 3065-3071 ◽  
Author(s):  
Peir-Yung Chu ◽  
Isabelle Campion ◽  
Relva C. Buchanan
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Phase Transformation ◽  
Heating Rate ◽  
Tetragonal Phase ◽  
Monoclinic Phase ◽  
Preferred Orientation ◽  
Si Substrate ◽  
Interfacial Diffusion ◽  
Deposited Films

Phase transformation and preferred orientation in ZrO2 thin films, deposited on Si(111) and Si(100) substrates, and prepared by heat treatment from carboxylate solution precursors were investigated. The deposited films were amorphous below 450 °C, transforming gradually to the tetragonal and monoclinic phases on heating. The monoclinic phase developed from the tetragonal phase displacively, and exhibited a strong (111) preferred orientation at temperature as low as 550 °C. The degree of preferred orientation and the tetragonal-to-monoclinic phase transformation were controlled by heating rate, soak temperature, and time. Interfacial diffusion into the film from the Si substrate was negligible at 700 °C and became significant only at 900 °C, but for films thicker than 0.5 μm, overall preferred orientation exceeded 90%.

Formation and Phase Stability of Tetragonal Phase in Rapidly Quenched ZrO2-ErO1.5

1988 ◽  
Vol 27 (Part 2, No. 9) ◽  
pp. L1757-L1760 ◽  
Author(s):  
Masahiro Yoshimura ◽  
Masatomo Yashima ◽  
Tatsuo Noma ◽  
Shigeyuki S\=omiya
Keyword(s):  
Phase Stability ◽  
Tetragonal Phase

scholarly journals Nucleation barriers at corners for a cubic-to-tetragonal phase transformation

2015 ◽  
Vol 145 (4) ◽  
pp. 715-724 ◽  
Author(s):  
Peter Bella ◽  
Michael Goldman
Keyword(s):  
Phase Transformation ◽  
Tetragonal Phase ◽  
Scaling Law ◽  
Energetic Cost ◽  
Minimal Energy ◽  
Physical Experiments ◽  
Domain With A Corner ◽  
Appl Math ◽  
Good Agreement

We are interested in the energetic cost of a martensitic inclusion of volume V in austenite for the cubic-to-tetragonal phase transformation. In contrast with the work of Knüpfer, Kohn and Otto (Commun. Pure Appl. Math.66 (2013), 867–904), we consider a domain with a corner and obtain a better scaling law for the minimal energy (Emin ∼ min(V2/3, V7/9)). Our predictions are in good agreement with physical experiments where nucleation of martensite is usually observed near the corners of the specimen.

Phase Stability and Mechanical Properties of Ti(Ni, Ru) Alloys

2002 ◽  
Vol 753 ◽  
Author(s):  
Masahiro Tsuji ◽  
Hideki Hosoda ◽  
Kenji Wakashima ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Phase Stability ◽  
Hot Forging ◽  
Tensile Tests ◽  
Lattice Parameter ◽  
Solid Solution Hardening ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Transmission Electron

ABSTRACTEffects of ruthenium (Ru) substitution on constituent phases, phase transformation temperatures and mechanical properties were investigated for Ti-Ni shape memory alloys. Ti50Ni50-XRuX alloys with Ru contents (X) from 0mol% (binary TiNi) to 50mol% (binary TiRu) were systematically prepared by Ar arc-melting followed by hot-forging at temperatures from 1173K to 1673K depending on chemical composition. Phase stability was assessed by DSC (differential scanning calorimetry), XRD (X-ray diffractometry) and TEM (transmission electron microscopy). Mechanical properties were investigated using hardness and tensile tests at room temperature. With increasing Ru content, it was found that the lattice parameter of B2 phase increases, the martensitic transformation temperature slightly decreases, and the melting temperature increases monotonously. Besides, R-phase appears for Ti-Ni alloys containing 3mol% and 20mol%Ru but no diffusionless phase transformation is seen in Ti-Ni alloy containing 5mol%Ru. Vickers hardness shows the maximum at an intermediate composition (HV1030 at 30mol%Ru); this suggests that large solid solution hardening is caused by Ru substitution for the Ni-sites in TiNi.

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