The Influence of Magnetoelastic Interaction on the First Transverse Sound in a Ferromagnet of Cubic Symmetry in a Vicinity of the Martensitic Transformation

2014 ◽  
Vol 59 (10) ◽  
pp. 1007-1012 ◽  
Author(s):  
A.G. Danilevich ◽  
2001 ◽  
Vol 16 (5) ◽  
pp. 1252-1255 ◽  
Author(s):  
Donglin Li ◽  
Pingchu Wang ◽  
Xiaoming Pan ◽  
Haosu Luo ◽  
Zhiwen Yin

Single crystals of 67Pb(Mg1/3Nb2/3)O3–33PbTiO3 (PMN-PT, PMNT) relaxor-based complex perovskite solid solution grown by Bridgman method have pseudo-cubic symmetry under ambient conditions. Examination by means of polarized light microscopy showed that the microstructure of the crystals was dominated by a large number of coarse twin domains. It was confirmed that the most common composition planes were {110} in addition, {112} planes were also observed. These twins may be associated with the transformation of PMNT complex perovskite from the cubic to tetragonal upon a decrease in temperatures. The morphology of the domain structure may be explained from the theory of martensitic transformation.


Author(s):  
R-R. Lee

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.


Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.


Author(s):  
Wenwu Cao

Domain structures play a key role in determining the physical properties of ferroelectric materials. The formation of these ferroelectric domains and domain walls are determined by the intrinsic nonlinearity and the nonlocal coupling of the polarization. Analogous to soliton excitations, domain walls can have high mobility when the domain wall energy is high. The domain wall can be describes by a continuum theory owning to the long range nature of the dipole-dipole interactions in ferroelectrics. The simplest form for the Landau energy is the so called ϕ model which can be used to describe a second order phase transition from a cubic prototype,where Pi (i =1, 2, 3) are the components of polarization vector, α's are the linear and nonlinear dielectric constants. In order to take into account the nonlocal coupling, a gradient energy should be included, for cubic symmetry the gradient energy is given by,


Author(s):  
Jenö Beyer ◽  
Lajos Tóth

The structural changes during reversible martensitic transformation of near-equiatomic NiTi alloys can best be studied in TEM at around room temperature. Ternary additions like Mn offer this possibility by suppressing the Ms temperature below RT. Besides the stable intermetallic phases (Ti2Ni, TiNi, TiNi3) several metastable phases with various crystallographic structures (rhombohedral, hexagonal, monoclinic, cubic) have also been reported to precipitate due to suitable annealing procedures.TiNi:Mn samples with 0.9 and 1.3 at% Mn were arc melted in argon atmosphere and homogenized at 948 °C for 72 hours in high vacuum in an infrared furnace. After spark cutting slices of 0.2 mm, TEM specimens were prepared by electrochemical polishing with the twin-jet technique in methanol - perchloric acid electrolyte. The TEM study was carried out in a JEOL 200 CX analytical electron microscope.In this paper a new intermetallic phase is reported which has been observed in both samples by TEM during the martensitic transformation process.


1978 ◽  
Vol 3 ◽  
pp. 479-501 ◽  
Author(s):  
E. Du Trémolet de Lacheisserie ◽  
P. Morin ◽  
J. Rouchy

1995 ◽  
Vol 05 (C8) ◽  
pp. C8-973-C8-978
Author(s):  
M. Jurado ◽  
Ll. Mañosa ◽  
A. González-Comas ◽  
C. Stassis ◽  
A. Planes

2003 ◽  
Vol 112 ◽  
pp. 495-498
Author(s):  
V. V. Kokorin ◽  
L. E. Kozlova ◽  
A. N. Titenko

Sign in / Sign up

Export Citation Format

Share Document