Thermoelectroc Power for Phase Transformation Study in Metallic Alloys

1982 ◽  
Vol 21 ◽  
Author(s):  
R. Borrelly ◽  
P. Merle ◽  
J. Merlin ◽  
J.M. Pelletier ◽  
G. Vigier
Keyword(s):  
Plastic Deformation ◽  
Phase Transformation ◽  
Short Range ◽  
Metallic Alloys ◽  
Cu Alloys ◽  
Short Range Ordering ◽  
Power Measurements ◽  
Transformation Study ◽  
Microstructure Of The Material ◽  
Thermoelectrical Power

ABSTRACTRecent experiments have proved the efficiency of T.E.P. measurements in phase transformation studies. The main features of the technique are presented and two particular examples of application are given (influence of plastic deformation on short range ordering (S.R.O.) and study of dissolution of the equilibrium Θ phase in Al-Cu alloys).Since the first studies [1] only very few attempts have been made to use thermoelectrical power measurements (T.E.P.) to characterize the evolution of an alloy during phase transformation. However, in spite of the complexity of the theoretical interpretations, T.E.P. measurements can give valuable informations on the microstructure of the material, sometimes with more easiness or more precision than with other techniques or even informations which would be impossible to obtain by another way.

scholarly journals Mössbauer Analysis of Deformation–Induced Acceleration of Short-Range Concentration Separation in Fe-Cr Alloys—Effect of the Substitution Impurity: Sb and Au

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 725
Author(s):  
Valery Shabashov ◽  
Kirill Kozlov ◽  
Yurii Ustyugov ◽  
Andrey Zamatovskii ◽  
Timofey Tolmachev ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Mössbauer Spectroscopy ◽  
Severe Plastic Deformation ◽  
Positron Annihilation ◽  
Temperature Region ◽  
Short Range ◽  
Mossbauer Spectroscopy ◽  
Short Range Ordering ◽  
Mössbauer Analysis ◽  
Effect Of Doping

The effect of doping the ferrite alloy Fe-16Cr by the oversized impurities Sb and Au on the mechanism of the short-range ordering induced by “warm” severe plastic deformation was studied using the method of Mössbauer spectroscopy. A comparison between the results obtained and the positron annihilation data on the evolution of the defects of vacancy type stabilized by the impurities Sb and Au was performed. It has been established that the impurities Sb and Au entail a shift of the temperature region of short-range ordering realization in conditions of applying pressure torsion towards greater temperatures by 250 and 100 K, respectively.

Relation between icosahedral short-range ordering and plastic deformation in Zr–Nb–Cu–Ni–Al bulk metallic glasses

2011 ◽  
Vol 59 (7) ◽  
pp. 2814-2822 ◽  
Author(s):  
Z.W. Zhu ◽  
L. Gu ◽  
G.Q. Xie ◽  
W. Zhang ◽  
A. Inoue ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Metallic Glasses ◽  
Short Range ◽  
Bulk Metallic Glasses ◽  
Short Range Ordering

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.

Evolution of order in amorphous-to-crystalline phase transformation of MgF2

2013 ◽  
Vol 46 (4) ◽  
pp. 1105-1116 ◽  
Author(s):  
Xiaoke Mu ◽  
Sridhar Neelamraju ◽  
Wilfried Sigle ◽  
Christoph T. Koch ◽  
Nico Totò ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Electron Diffraction ◽  
Short Range ◽  
Volume Fraction ◽  
Metastable Phase ◽  
Dynamics Simulation ◽  
Structure Evolution ◽  
Stable Phase ◽  
Type Phase ◽  
Short Range Ordering

Structural disorder and distortion play a significant role in phase transformations. Experimentally, electron diffraction in the transmission electron microscope offers the ability to characterize disorderviathe pair distribution function (PDF) at high spatial resolution. In this work, energy-filteredin situelectron diffraction is applied to measure PDFs of different phases of MgF2from the amorphous deposit through metastable modifications to the thermodynamically stable phase. Despite the restriction of thick specimens resulting in multiple electron scattering, elaborate data analysis enabled experimental and molecular dynamics simulation data to be matched, thus allowing analysis of the evolution of short-range ordering. In particular, it is possible to explain the theoretically not predicted existence of a metastable phase by the presence of atomic disorder and distortion. The short-range ordering in the amorphous and crystalline phases is elucidated as three steps: (i) an initial amorphous phase exhibiting CaCl2-type short-range order which acts as a crystallization nucleus to guide the phase transformation to the metastable CaCl2-type phase and thus suppresses the direct appearance of the rutile-type phase; (ii) a metastable CaCl2-type phase containing short-range structural features of the stable rutile type; and (iii) the formation of a large volume fraction of disordered intergranular regions which stabilize the CaCl2-type phase. The structure evolution is described within the energy landscape concept.

Onset of Θ' to Θ Phase Transformation in Al-Cu Alloys

2019 ◽  
Author(s):  
Patrick Shower ◽  
James R. Morris ◽  
Dongwon Shin ◽  
Lawrence F. Allard ◽  
Balasubramaniam Radhakrishnan ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Cu Alloys
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