Low-Temperature Behavior of a Face-Centered Cubic Antiferromagnet

1964 ◽  
Vol 133 (5A) ◽  
pp. A1344-A1349 ◽  
Author(s):  
A. Danielian
Keyword(s):  
Low Temperature ◽  
Temperature Behavior ◽  
Face Centered Cubic ◽  
Face Centered

scholarly journals Microstructure Refinement by Low-Temperature Ausforming in an Fe-Based Metastable High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 742
Author(s):  
Motomichi Koyama ◽  
Takeaki Gondo ◽  
Kaneaki Tsuzaki
Keyword(s):  
Low Temperature ◽  
Plastic Anisotropy ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Microstructure Refinement ◽  
Hexagonal Close Packed ◽  
Solution Treated Condition ◽  
Solution Treated ◽  
Face Centered

The effects of ausforming in an Fe30Mn10Cr10Co high-entropy alloy on the microstructure, hardness, and plastic anisotropy were investigated. The alloy showed a dual-phase microstructure consisting of face-centered cubic (FCC) austenite and hexagonal close-packed (HCP) martensite in the as-solution-treated condition, and the finish temperature for the reverse transformation was below 200 °C. Therefore, low-temperature ausforming at 200 °C was achieved, which resulted in microstructure refinement and significantly increased the hardness. Furthermore, plasticity anisotropy, a common problem in HCP structures, was suppressed by the ausforming treatment. This, in turn, reduced the scatter of the hardness.

The Bismuth-Barium Oxides

1998 ◽  
Vol 547 ◽  
Author(s):  
K. Müller ◽  
J.K. Meen ◽  
D. Elthon
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Low Temperature ◽  
Phase Relations ◽  
The Other ◽  
Face Centered Cubic ◽  
Polymorphic Transformations ◽  
Face Centered ◽  
T Phase

AbstractPhase relations have been determined for the Bi-Ba oxide pseudobinary up to 50 cat % Ba in 1 atm of oxygen at 640°-1000°C. The low-temperature α-Bi2O3 polymorph does not dissolve appreciable BaO. All other phases in the system have significant ranges of solution. The δ-Bi2O3 polymorph, stable from 730°C to 825°C is an end-member of a face-centered cubic solid solution (FCCss) that dissolves up to 2.7 % Ba. Ba-saturated FCCss and Bi-saturated rhombohedral (ß) solid solution (6.3 % Ba) melt at a eutectic at 753 °C. Less Bi is needed to saturate the ß phase at lower temperatures so α-Bi2O3 coexists with a ß phase containing 11.5 % Ba at 646°C.The amount of Ba required to saturate the ß phase depends less strongly on temperature. Ba-saturated ß phase contains 19 % Ba at 700°C. These ß materials are in equilibrium with an oxide near Bi3BaO5.5 that undergoes two polymorphic transformations: low-temperature cubic (<700°C); orthorhombic (700-730°C); high-temperature cubic (Cht). There is a eutectic between the ß and Cht, at 775±6°C. At T<700°C, 26.5 % Ba saturates the latter but it can take in up to 29.5 % Ba (at 812°C). At T<815°C the coexisting phase is BiBaO3. A tetragonal (T) phase forms by reaction of Ch, and BiBaO3 and has ~35% BaO at 815°C. The composition span of T widens as temperature increases. Cht, melts incongruently at 820°C to a liquid and T with 29.8 % Ba. Above that temperature the Bi-saturated and Ba-saturated T phases both become more Ba-rich as temperature is elevated. T melts incongruently to liquid and BiBaO3.The δ-Bi2O3 and ß, both anion conductors, have structures based on that of fluorite. The other oxides have perovskite-like structures. Half of the Bi in BiBaO3 is pentavalent and half is trivalent. The other oxides appear to have all their Bi in the 3+ state.

Synthesis of Monodisperse FePt Nanoparticles at a Low Temperature

2007 ◽  
Vol 124-126 ◽  
pp. 899-902
Author(s):  
Hui Ping Shao ◽  
Yu Qiang Huang ◽  
Hyo Sook Lee ◽  
Yong Jae Suh ◽  
Chong Oh Kim
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Thermal Annealing ◽  
Crystalline Structure ◽  
Fept Nanoparticles ◽  
Face Centered Cubic ◽  
Face Centered

Monodisperse FePt nanoparticles were synthesized by thermal decomposition of Fe(CO)5 and reduction of Pt(acac)2 at low temperature of 160–180 °C by using kerosene as a solvent. The average sizes of the synthesized particles ranged from 2.2 to 4.4 nm. Thermal annealing of the as-prepared FePt particles at 700 °C for 1 h transformed the crystalline structure of the particles from a disordered face-centered cubic to an ordered face-centered tetragonal. This change led to a significant increase in coercivity from 153.37 to 2273.22 Oe and in saturated magnetization from 26.86 to 41.21 emu/g.

LOW TEMPERATURE CREEP AND STRESS RELAXATION FOR PEIERLS BARRIER IN CUBIC METALS

1995 ◽  
Vol 09 (05) ◽  
pp. 285-289 ◽  
Author(s):  
S. A. MAJEED ◽  
N. FAROOQUI ◽  
M. A. AHMED ◽  
S. M. RAZA
Keyword(s):  
Stress Relaxation ◽  
Low Temperature ◽  
Activation Volume ◽  
Face Centered Cubic ◽  
Cubic Metals ◽  
Temperature Creep ◽  
Peierls Barrier ◽  
Face Centered ◽  
Low Temperature Creep ◽  
Creep And Stress Relaxation

The relation for low temperature creep and stress relaxation is developed for Peierls barrier in cubic metals using single barrier stochastic model, with special reference to face-centered cubic crystals. Our conjecture that the strain enhancement is responsible for an increase in activation volume is verified through nondimensionality, i.e. by shear traction number.

Vapor phase dealloying-driven synthesis of bulk nanoporous cobalt with a face-centered cubic structure

CrystEngComm ◽  
2021 ◽  
Author(s):  
Yujun Shi ◽  
Yu Wang ◽  
Wanfeng Yang ◽  
Jingyu Qin ◽  
Qingguo Bai ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Vapor Phase ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Cubic Structure ◽  
Hcp Structure ◽  
Face Centered ◽  
Fcc Structure

Cobalt (Co) mainly exists in two allotropic forms: a low temperature hexagonal close-packed (HCP) structure and a high temperature face centered cubic (FCC) structure. However, annealing at high temperature only...

Crystallographic Studies of NH4Cl—NH4Br Solid Solutions

1965 ◽  
Vol 9 ◽  
pp. 159-169 ◽  
Author(s):  
Jane Edmund Callanan ◽  
Norman O. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Solid Solutions ◽  
Room Temperature ◽  
Ammonium Bromide ◽  
Face Centered Cubic ◽  
Lattice Constants ◽  
Temperature Work ◽  
Face Centered ◽  
Slight Positive Deviation

AbstractBoth ammonium chloride and ammonium bromide undergo a transition, with rise in temperature, from an interpenetrating simple cubic (II) to a face-centered cubic (I) lattice at 183 and 137°C, respectively, and both the low- and high-temperature forms give a complete series of solid solutions. We have determined the lattice constants of the high-temperature solids at about 250° as a function of composition, and redetermined the lattice constants of the low-temperature solids at room temperature. The solutions were made by crystallization from water, followed by stirring in contact with mother liquor for at least three weeks at room temperature. Measurements were made with a Norelco- Philips diffractometer and recorder, with Cu Ko. radiation. For the high-temperature work, a simple, inexpensive heating apparatus was developed. The only previous data reported for the high-temperature forms are the lattice constants of the pure components given by Bartlett and Langmuir.The low-temperature solutions showed negative deviations from Vegard's rule at both ends of the concentration range and a slight positive deviation elsewhere when high-angle data were used. The high-temperature solutions showed marked positive deviations from Vegard's rule over the whole compositions range. Values for the pure components agreed reasonably well with those of Bartlett and Langmuir.The progress of the change II → I with time was followed for some of the solutions in the neighborhood of the transition temperature in an attempt to reveal the mechanism of the process.

Sign in / Sign up

Export Citation Format

Share Document