PLASTICITY OF IRON SINGLE CRYSTALS

1967 ◽  
Vol 45 (2) ◽  
pp. 1101-1120 ◽  
Author(s):  
A. S. Keh ◽  
Y. Nakada

Results accumulated in the past four years on the plastic deformation of iron single crystals are summarized.The work-hardening behavior of iron single crystals depends very much on orientation and temperature. At room temperature, three-stage hardening was observed for single-slip orientations. The work-hardening rates in stages I and II were correlated with the extent of localized secondary slip.Latent hardening was observed in iron crystals. The latent-hardening ratio is about 1.3 and is relatively independent of temperature and choice of latent system.The yield stress of iron single crystals is very dependent on temperature and is also sensitive to orientation at low temperatures and to interstitial content at all temperatures. By adding interstitials to purified crystals, the athermal portion of the flow stress of iron is raised, but its temperature dependence is not altered. Crystals oriented for single slip on the (101) and (112) planes have different temperature dependences of the proportional limit. Similar but small differences in this temperature dependence of proportional limits were observed in crystals oriented for single, double, and multiple slip on {112} planes. These results are explained on the basis of a Peierls mechanism.

1994 ◽  
Vol 364 ◽  
Author(s):  
S. S. Ezz ◽  
Y. Q. Sun ◽  
P. B. Hirsch

AbstractThe strain rate sensitivity ß of the flow stress τ is associated with workhardening and β=(δτ/δln ε) is proportional to the workhardening increment τh = τ - τy, where τy is the strain rate independent yield stress. The temperature dependence of β/τh reflects changes in the rate controlling mechanism. At intermediate and high temperatures, the hardening correlates with the density of [101] dislocations on (010). The nature of the local obstacles at room temperature is not established.


1999 ◽  
Vol 13 (29n31) ◽  
pp. 3758-3763 ◽  
Author(s):  
AUGUST YURGENS ◽  
DAG WINKLER ◽  
TORD CLAESON ◽  
SEONG-JU HWANG ◽  
JIN-HO CHOY

The c-axis tunneling properties of both pristine Bi2212 and its HgBr 2 intercalate have been measured in the temperature range 4.2-250 K. Lithographically patterned 7-10 unit-cell heigh mesa structures on the surfaces of these single crystals were investigated. Clear SIS-like tunneling curves for current applied in the c-axis direction have been observed. The dynamic conductance d I/ d V(V) shows both sharp peaks corresponding to a superconducting gap edge and a dip feature beyond the gap, followed by a wide maximum, which persists up to a room temperature. Shape of the temperature dependence of the c-axis resistance does not change after the intercalation suggesting that a coupling between CuO 2-bilayers has little effect on the pseudogap.


1989 ◽  
Vol 03 (04) ◽  
pp. 295-299 ◽  
Author(s):  
G.H. CHEN ◽  
J.H. WANG ◽  
D.N. ZHENG ◽  
Y.F. YAN ◽  
S.L. JIA ◽  
...  

The thermopower in single crystals of the high T c superconductor Bi 2 Sr 2 CaCu 2 O y has been measured in both a-b plane (S ab ) and along c axis (Sc) respectively. The temperature dependences are distinctly anisotropic. S c increases monotonously with temperature and is positive from T c to room temperature, while S ab increases rapidly near T c and then decreases with temperature. The maximum of S ab is at 115 K and S ab changes its sign at 250 K.


2018 ◽  
Vol 186 ◽  
pp. 02010
Author(s):  
A.B. Petrova ◽  
A.V. Malyshev ◽  
A.P. Surzhikov

The article presents the results of a study of the effect of mechanical load on the temperature dependence of the initial permeability of LiTiZn soft ferrite ceramics. Regimes of mechanical load were created by a steel non-magnetic ring with screws. In this work, four levels of mechanical load were investigated: without load, with 1, 2 and 3 screws. For obtaining temperature dependences and exclude the influence of prehistory on the initial permeability, the samples were heated to a temperature exceeding the Curie point by 50 degrees, after which they slowly cooled to room temperature. The defects level was determined by the ratio of the parameters β / α of the phenomenological expression, which describes the experimental temperature dependences. It is shown that as the mechanical load increases, the defects level of ferrite ceramics increases, and after load removing, it returns to its original level.


1986 ◽  
Vol 41 (1-2) ◽  
pp. 382-385 ◽  
Author(s):  
J. Kasprzak ◽  
J. Lus ◽  
J. Pietrzak

The 63Cu and 65Cu NQR transitions in powder samples of cuprous oxide have been investigated from 77 to 500 K and at room temperature after annealing up to 1100 K Significant differences in T1 , NQR linewidth Δv, and their temperature dependences were found among the samples prepared in different ways. For C u20 samples obtained in low temperatures (below 380 K), the temperature dependence of T1 below 380 K is o f activation character with Ea = 0.07 eV. These results are interpreted in terms of an electron hopping mechanism. Thermal processing of these samples permits to obtain irreversible electronic state and then the spectroscopic parameters are the same as for the samples obtained in high temperatures (above 1320 K).


2007 ◽  
Vol 561-565 ◽  
pp. 459-462
Author(s):  
Katsushi Tanaka ◽  
Hiromitsu Ide ◽  
Yoshinori Sumi ◽  
Kyosuke Kishida ◽  
Haruyuki Inui

Compressive deformation of L10-ordered single crystals of FePd whose c/a ratio less than unity have been investigated from room temperature to 823 K. The results show that the critical resolved shear stress (CRSS) for octahedral glide of ordinary dislocations is smaller than that of super-lattice dislocations in all the temperature range investigated, that is the opposite sense to the case of Ti-56 mol% Al. The CRSS for ordinary dislocations virtually independent to the temperature. On the other hand, the CRSS for super dislocations exhibits a weak positive temperature dependence from room temperature up to 573 K and decreases in higher temperatures.


1994 ◽  
Vol 348 ◽  
Author(s):  
Ivan Shmyt'ko ◽  
I.B. Savchenko ◽  
N.V. Klassen ◽  
B.Sh. Bagautdinov ◽  
G.A. Emel'chenko ◽  
...  

ABSTRACTAn anomaly of the temperature dependence of the unit cell parameter has been observed for β–PbF2 single crystals at 200 K that is interpreted as a phase transition to a pseudocubic lattice. Such a pseudocubic phase is observable at room temperature after uniaxial plastic deformation of the bulk single crystals. The structural aspects of the β→α transition have been established. The as-grown crystals of α–PbF2 phase are shown to undergo a phase transition at 100 K.


1990 ◽  
Vol 31 (2) ◽  
pp. 118-128 ◽  
Author(s):  
J. Kumagai ◽  
S. Takaki ◽  
S. Suzuki ◽  
H. Kimura

2018 ◽  
Vol 60 (11) ◽  
pp. 2116
Author(s):  
Е.Е. Пестов ◽  
Ю.Н. Ноздрин ◽  
А.И. Елькина ◽  
Ю.C. Ерин ◽  
М. Лю ◽  
...  

Abstract —Temperature dependences of the third-harmonic power for the (Na_0.3K_0.7)_ x Fe_2 – _ y Se_2 sodium–potassium ferroselenide single crystals have been investigated by nonlinear near-field microwave microscopy. The temperature dependence of magnetic susceptibility at a frequency of 100 kHz for this compound has been measured. The experimental results suggest a double-gap structure of the (Na_0.3K_0.7)_ x Fe_2 – _ y Se_2 superconductor.


2019 ◽  
Vol 181 ◽  
pp. 555-569 ◽  
Author(s):  
S. Picak ◽  
J. Liu ◽  
C. Hayrettin ◽  
W. Nasim ◽  
D. Canadinc ◽  
...  

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