Room-temperature-deformation-induced chemical short-range ordering in a supersaturated ultrafine-grained Al-Zn alloy

2022 ◽  
Vol 210 ◽  
pp. 114423
Author(s):  
Z.Z. Song ◽  
R.M. Niu ◽  
X.Y. Cui ◽  
E.V. Bobruk ◽  
M. Murashkin ◽  
...  
Keyword(s):  
Short Range ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Ultrafine Grained ◽  
Short Range Ordering ◽  
Zn Alloy

Relaxation during short-range-ordering in Cu-30% Zn alloy

1972 ◽  
Vol 22 (12) ◽  
pp. 1269-1272 ◽  
Author(s):  
T. H. Youssef
Keyword(s):  
Short Range ◽  
Short Range Ordering ◽  
Zn Alloy

Aging-induced double hysteresis loops in bismuth-doped (Ba,Ca)TiO3 ferroelectric ceramics

2009 ◽  
Vol 24 (10) ◽  
pp. 3073-3077 ◽  
Author(s):  
Sining Yun ◽  
Xiaoli Wang ◽  
Jing Shi ◽  
Delong Xu
Keyword(s):  
Solid State ◽  
Point Defects ◽  
Short Range ◽  
Room Temperature ◽  
Domain Switching ◽  
Hysteresis Loops ◽  
Ferroelectric Ceramics ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Short Range Ordering

Bismuth-doped (Ba1−xCax)TiO3 ceramics (x = 0.10, Bi-BCT) were prepared by a conventional solid-state reaction technique. An abnormal double-like hysteresis polarization–electric (P–E) loop was observed at room temperature for aged Bi-BCT. Raman scattering gives critical evidence for the formation of O2− vacancies in Bi-BCT. The change from the single P–E loops in the fresh samples to the double loops in the aged samples excludes the existence of a ferroelectric–antiferroelectric transition in Bi-BCT. A reversible domain switching mechanism resulting from a symmetry-conforming short-range ordering of point defects gives a reasonable explanation for the naturally age-induced double-like P–E loops in Bi-BCT.

Room-Temperature Short-Range Ordering in Fe-Si Alloys Observed by Internal Friction

2008 ◽  
Vol 137 ◽  
pp. 83-90
Author(s):  
Fernando González ◽  
Daniel Ruiz ◽  
Yvan Houbaert
Keyword(s):  
Internal Friction ◽  
Cold Rolling ◽  
Short Range ◽  
Room Temperature ◽  
Ageing Time ◽  
Low Carbon ◽  
New Production ◽  
Short Range Ordering ◽  
Si Content ◽  
Ageing Phenomenon

Research performed at Ghent University, regarding new production methods for electrical steel, has shown that high silicon steel suffers an ageing phenomenon at room temperature. Recent studies carried out by the same group using different analysis techniques (Mossbauer spectroscopy, neutron diffraction, etc) brought to light a probable process of ordering towards the D03-structure, which is responsible for the observed low ductility during cold rolling and makes the processing of steel extremely difficult. In addition, the Si-steels become more brittle as the delay time between hot and cold rolling is increased. Frequency dependent internal friction (FDIF) studies were performed on different Fe - Si alloys with a Si content varying from 3.73 at. % to 8.7 at. % immediately after several thermal treatments and compared with ultra-low carbon steel. The evolution of relaxation peaks during the IF measurements, performed at constant room temperature, helps to understand the ageing mechanisms. Three processes have been observed: firstly, as expected, addition of Si reduces the carbon Snoek peak. Secondly, a peak associated to C - Si is formed. Thirdly, a low frequency peak associated with Zener relaxation (Si atom pairs) appears for a content of approximately 3.77 wt. % Si. The two latter peaks decrease with ageing time and in the case of the Zener peak there is a notable displacement to higher frequencies with a small increase of the Si content. The reduction of the peaks during the ageing after annealing is more noticeable in quenched specimens than in air cooled ones, and in furnace cooled specimens the reduction is even smaller, indicating that the process is really an ageing phenomenon. Room temperature short-range ordering might explain both the lowering of the Zener peak and the observed macroscopic embrittlement.

The Comparative Mössbauer Analysis of Superfine Structure of Hadfield Steel upon Different Kinds of Severe Deformation

2011 ◽  
Vol 319-320 ◽  
pp. 13-23 ◽  
Author(s):  
V.A. Shabashov ◽  
A.E. Zamatovsky ◽  
L.G. Korshunov ◽  
A.V. Litvinov
Keyword(s):  
Plastic Deformation ◽  
Short Range ◽  
Room Temperature ◽  
Precipitation Hardening ◽  
Effective Field ◽  
Hadfield Steel ◽  
Magnetic Characteristics ◽  
Short Range Ordering ◽  
Superfine Structure ◽  
Mössbauer Analysis

Severe plastic deformation (friction, compression shear, filing or rolling) of Hadfield steel leads to the growth of the internal effective field on 57Fe cores, removal of the magnetic degeneracy in spectra, and the extension of the paraprocess up to room temperature. The observed change of the magnetic characteristics is explained by the deformation-induced redistribution of carbon and short-range ordering of carbon and manganese. Since the magnetic degeneracy is removed in the Hadfield steel upon deformation, it is possible to consider a mechanism of magnetic precipitation hardening, which is realized in local magnetically ordered regions of the structure containing Mn-C pairs.

scholarly journals Softening Behaviors of Severely Deformed Zn Alloy Studied by the Nanoindentation

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 803
Author(s):  
Jiangjiang Hu ◽  
Shuo Sun ◽  
Wei Zhang ◽  
Guangjian Peng ◽  
Shuang Han ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Sliding Friction ◽  
Coarse Grained ◽  
Lower Stress ◽  
Friction Treatment ◽  
Ultrafine Grained ◽  
Dislocation Reaction ◽  
Deformed Layer ◽  
Zn Alloy

Zamak 3 alloy treatment by sliding-friction treatment (SFT) was investigated by nanoindentation to explore the influence of microstructure and strain rate on nanoscale deformation at room temperature. The results show that obvious material softening occurs in the ultrafine-grained (UFG) Zn alloy and strain-hardening happens in the twinning-deformed layer, respectively. It can be concluded that almost constant values of V in the UFG Zn alloy contribute to the dislocations moving along the grain boundary (GB) not cross the grain interior. In the twinning-deformed layer, the highly frequent dislocation–twinning boundary (TB) interactions are responsible for subsequent inverse Cottrell–Stokes at lower stress, which is quite different from dislocation–dislocation reaction inside the grain in their coarse-grained (CG) counterpart.

Enhanced Ductility in Ultrafine-Grained Al Alloys Produced by SPD Techniques

2009 ◽  
Vol 633-634 ◽  
pp. 321-332 ◽  
Author(s):  
Ruslan Valiev ◽  
Maxim Yu. Murashkin ◽  
Boris B. Straumal
Keyword(s):  
Room Temperature ◽  
High Pressure Torsion ◽  
High Strength ◽  
Al 6061 ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Processing Regimes ◽  
Zn Alloy ◽  
Strength And Ductility

In this work ultrafine-grained (UFG) structure was successfully produced in the commercial Al 6061 and Al-30%Zn alloys using new modifications of two severe plastic deformation (SPD) techniques, namely equal channel angular pressing (ECAP) with parallel channels (PC) and high pressure torsion (HPT) with enhanced load. Variation of SPD processing regimes made it possible not only to perform strong grain refinement but also to modify the phase composition through the formation of grain boundary (GB) segregations and precipitations. This enabled to achieve a unique combination of high strength and ductility in the Al 6061 alloy and demonstrate super-ductility in the Al-30%Zn alloy, when elongation to failure exceeded 150% at room temperature.

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