Models of Mutual Solubility Increasing under the Pulse Loading

2008 ◽  
Vol 277 ◽  
pp. 69-74
Author(s):  
Andriy O. Koval'chuk ◽  
D.S. Gertsriken ◽  
Andriy Gusak ◽  
V.F. Mazanko

Since 1975 a so-called anomalous mass-transfer in metals and alloys under pulse loading is being investigated in the Institute of Metal Physics. This phenomenon remains to be a challenge to theoreticians. Besides, one more phenomenon (observed at the same systems) was discovered – formation of metastable alloys (solutions, and, sometimes, ordered phases), with solubility limits far exceeding the equilibrium values and depending on the deformation rate. Since formation of nonequilibrium phases is also typical for alloys under irradiation, it seemed natural for us to use some of concepts and models invented in the “materials under irradiation” community. We propose 3 types of models for description of metastable solid solution formation in diffusion couple under pulse loading: 1) flux balance for both components at the interface with account of non-equilibrium defects generated during pulse loading; 2) “ballistic jump” concept, which had been invented by George Martin et al. for materials under irradiation or ball-milling, combined with another Martin’s kinetic model (1994) of diffusion; 3) modification of such a concept for the case of non-equilibrium interstitial defects. Non-equilibrium phase diagrams obtained by all 3 models are built and compared with experimental data which reflect a qualitative correspondence to one another.

Author(s):  
T. R. Dinger

Zirconia (ZrO2) is often added to ceramic compacts to increase their toughness. The mechanisms by which this toughness increase occurs are generally accepted to be those of transformation toughening and microcracking. The mechanism of transformation toughening is based on the presence of metastable tetragonal ZrO2 which transforms to the monoclinic allotrope when stressed by a propagating crack. The decrease in volume which accompanies this transformation effectively relieves the applied stress at the crack tip and toughens the material; microcrack toughening arises from the deflection of a propagating crack around sharply angular inclusions.These mechanisms, however, do not explain the toughness increases associated with the class of composites investigated here. Analytical electron microscopy (AEM) has been used to determine whether solid solution effects could be the cause of this increased toughness. Specimens of a mullite (3Al2O3·2SiO2) + 15 vol. % ZrO2 were prepared by the usual technique of mechanical thinning followed by ion beam milling. All observations were made in a Philips EM400 TEM/STEM microscope fitted with EDXS and EELS spectrometers.


1986 ◽  
Vol 47 (C1) ◽  
pp. C1-441-C1-445
Author(s):  
E. KOSTIĆ ◽  
S. J. KISS ◽  
D. CEROVIĆ

2000 ◽  
Vol 11 (20) ◽  
pp. 4061-4070 ◽  
Author(s):  
Orsolya Barabás ◽  
Dóra K Menyhárd ◽  
Zsolt Böcskei ◽  
Kálmán Simon ◽  
Ilona Kiss-Ajzert ◽  
...  

2014 ◽  
Vol 783-786 ◽  
pp. 766-770
Author(s):  
Yan Lin He ◽  
Na Qiong Zhu ◽  
Wei Sen Zheng ◽  
Xiao Gang Lu ◽  
Lin Li

The non-equilibrium microstructure of Fe-C-Mn-Si TRIP steel is designed bythermodynamic and kinetic calculation. The upper limit of bainitic transformation temperature iscalculated and compared to that characterized by CCT curve determination. s M temperature isdetermined based on thermodynamics of martensitic transformation and sublattice model. Thecalculation is conducted via TQ6-patch in Thermo-Calc software. Comparison between thecalculations and experiments reveals the relationship between non-equilibrium phase compositionand heat treatment parameters which can be utilized to achieve the elaborate design of alloy and heattreatment for super TRIP steel.


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