scholarly journals A magnetic study of the two-phase iron-nickel alloys

1940 ◽  
Vol 175 (962) ◽  
pp. 331-344 ◽  
Keyword(s):  
Thermal Hysteresis ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Two Phase ◽  
Saturation Intensity ◽  
Visual Evidence ◽  
Magnetic Investigation ◽  
Iron Nickel ◽  
Lower Temperature ◽  
Iron Nickel Alloys

The iron-rich alloys of iron and nickel resemble pure iron in that they undergo a phase change from body-centred cubic ( α ) structure to face-centred cubic ( γ ) structure on heating. On cooling the alloys, however, the return to the original state takes place at a much lower temperature, and on account of this thermal hysteresis the alloys are known as irreversible. A magnetic investigation of these alloys has been made by Peschard (1925), who measured the variation of the saturation intensity of the alloys with temperature. The change from the α to the γ lattice is accompanied by a decrease of the saturation intensity of the alloy, since the γ phase is non-magnetic at the temperature of the change. Curves showing the variation of intensity with temperature are very useful in the study of these alloys, since they give visual evidence of the irreversibility. The relation of the irreversible changes to the equilibrium phase diagram is not clearly understood. Recently, however, equilibrium diagrams of the iron-nickel system, determined by means of X-ray data, have been published by Bradley and Goldschmidt (1939) and Owen and Sully (1939).

scholarly journals A magnetic study of the two-phase iron-nickel alloys. II

1943 ◽  
Vol 181 (986) ◽  
pp. 303-313 ◽  
Keyword(s):  
Nickel Alloys ◽  
Equilibrium Diagram ◽  
Equilibrium Phase ◽  
Equilibrium Concentration ◽  
Phase Segregation ◽  
Two Phase ◽  
Saturation Intensity ◽  
Iron Nickel ◽  
Practical Limit ◽  
Iron Nickel Alloys

The method of using measurements of magnetic saturation intensity of annealed iron-nickel alloys for the determination of the equilibrium phase boundaries, as demonstrated by Pickles & Sucksmith, has been extended. The phase diagram of the system has been determined accurately between 525 and 365° C. The mechanism of phase segregation from the single-phase a-state has been studied, where it was found that contrary to the usual case, one of the phases crystallizes out in its equilibrium concentration whilst the residue of the alloy progressively and uniformly approaches equilibrium com position. It was possible to study and express quantitatively the rate of attainment of equilibrium , and on evidence obtained in this way the view is based that the lower practical limit of temperature where the equilibrium diagram can be studied by annealing experiments has been reached.

A Morphology of Diffusion Zone from Entropy Production Calculations

2014 ◽  
Vol 1 ◽  
pp. 31-45 ◽  
Author(s):  
M. Danielewski ◽  
B. Wierzba ◽  
K. Tkacz-Śmiech
Keyword(s):  
Diffusion Zone ◽  
Initial Conditions ◽  
Equilibrium Phase ◽  
Diffusion Path ◽  
Alloy Coating ◽  
Equilibrium Phase Diagram ◽  
Advanced Materials ◽  
Two Phase ◽  
Three Phase ◽  
Phase Layers

Interdiffusion plays a significant role in the formation and stability of metallic joints and coatings. It is also of critical importance in designing advanced materials. Because commercial alloys are usually multicomponent, the key target is prediction of a complex morphology of the diffusion zone which grows between the alloys, alloy-coating, etc. In a two-component system, the diffusion zone can be composed of single-phase layers of the intermetallic compounds and solid solutions. The evolution of the composition and thicknesses of such layers are fairly well understood and consistent with the phase diagrams. The situation is qualitatively different in multicomponent systems. For example, the diffusion zone in a ternary system can be composed of single-and two-phase sublayers. Their number and thicknesses depend on the initial conditions, i.e. composition, component diffusivities and geometry of the system. The usual way of presenting the sequence of the layers and their compositions is by drawingadiffusionpathwhich is, by definition,a mapping of thestationary concentrations onto the isothermal section of the equilibrium phase diagram. The diffusion path connects initial compositions of the diffusion couple and can go across the single-, two-and three-phase fields. It starts at the composition of one alloy and ends at the other. The possibility of mapping the concentration profiles onto the ternary isotherm has been postulated in one from the seventeen theorems by Kirkaldy and Brown [] for the diffusion path. The detailed presentation of all theorems was recently done by Morral []. Here we remind the reader only of the chosen ones (shown in italics).

Mass transport of carbon in one and two phase iron-nickel alloys in a temperature gradient

1982 ◽  
Vol 13 (10) ◽  
pp. 1713-1719 ◽  
Author(s):  
I. C. I. Okafor ◽  
O. N. Carlson ◽  
D. M. Martin
Keyword(s):  
Temperature Gradient ◽  
Mass Transport ◽  
Nickel Alloys ◽  
Two Phase ◽  
Iron Nickel ◽  
Iron Nickel Alloys

MODELING MESOSCALE DYNAMICS OF FORMATION OF δ′-PHASE IN Al-Li ALLOYS

1993 ◽  
Vol 07 (16) ◽  
pp. 1083-1094
Author(s):  
R.S. GOLDSTEIN ◽  
M.F. ZIMMER ◽  
Y. OONO
Keyword(s):  
Minimal Model ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Phase System ◽  
Two Phase ◽  
Mesoscale Dynamics ◽  
Model Free ◽  
Model Study ◽  
Δ Phase ◽  
Ordered State

A mesoscale minimal model study of the α−δ′ two-phase system is presented. A minimal model free energy is introduced which reveals universal features of the ordering dynamics of the disordered into the L1 2 ordered state. Static phenomenological parameters of the minimal model are chosen to reproduce the equilibrium phase diagram, and dynamical ones are chosen to reproduce recent experimental scattering results by H. Chen’s group.

Can Amortization Bs Induced by Ion Mixing in Ag-Cu and Ag-Ni Systems?

1985 ◽  
Vol 54 ◽  
Author(s):  
B. X. Liu ◽  
L. J. Huang ◽  
J. Li ◽  
S. Ma
Keyword(s):  
Phase Diagram ◽  
Amorphous Phase ◽  
Equilibrium Phase ◽  
Structural Difference ◽  
Liquid Nitrogen Temperature ◽  
Equilibrium Phase Diagram ◽  
Heat Of Formation ◽  
Phase Region ◽  
Two Phase ◽  
Amorphous Phase Formation

ABSTRACTThe extended Structural Difference Rule for amorphous phase formation states that an amorphous phase can be obtained by ion mixing with an alloy with a composition lying in a two-phase region in the equilibrium phase diagram. This criterion has to respond to the challenge that no amorphous alloy has been formed in some early studied systems exhibiting a two-phase region character, e.g. Ag-Cu(typical eutec-tic),Ag-Ni(almost entirely immiscible),etc‥We performed ion mixing experiments for several systems at liquid nitrogen temperature using Xe ions with low current density. Amorphization was indeed observed in both Ag-Cu and Ag-Ni samples, as two halos were seen by TEM SAD immediately after adequate doses ion mixing. These not only support our two-pnase region rule, but also show the possibility of amorphization in a system(Ag-Ni) that has large positive heat of formation.

Calculation of the Mg-Gd-Y Alloy Equilibrium Phase Diagram and its Verification at 450°C

2013 ◽  
Vol 275-277 ◽  
pp. 1896-1903
Author(s):  
Yong Chun Guo ◽  
Ying Ming Sang ◽  
Jian Ping Li ◽  
Zhong Yang
Keyword(s):  
Phase Diagram ◽  
Phase Equilibrium ◽  
Diffusion Layer ◽  
Single Phase ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Atomic Diffusion ◽  
Diffusion Couples ◽  
Equilibrium Calculation ◽  
Two Phase

The Mg-Gd alloy, Mg-Y alloy equilibrium phase diagram has been characterized using the multiple phase equilibrium calculation software (Pandat) and the magnesium alloy thermodynamic database. The Mg-Gd and Mg-Y diffusion couples were made by the rivet method. According to the local balance principle, these diffusion couples were processed using an equalization treatment at 450 °C, followed by EDS analysis with a scanning electron microscope. The results show that a concentration gradient resulting from atomic diffusion is apparent in the Mg-Y and Mg-Gd diffusion layer, showing that the diffusion layers belong to different phases. There are 5 two-phase regions and 2 single phase regions in the Mg-Gd diffusion layer and 4 two-phase regions and 2 single phase regions in the Mg-Y diffusion layer. These results are consistent with the data from the phase equilibrium calculation. This research can provide experimental support for the Mg-Gd-Y three element alloy phase diagram calculation.

scholarly journals Phase Formation, Microstructure and Mechanical Properties of Mg67Ag33 as Potential Biomaterial

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 461
Author(s):  
Konrad Kosiba ◽  
Konda Gokuldoss Prashanth ◽  
Sergio Scudino
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Equilibrium Phase ◽  
Antibacterial Properties ◽  
Equilibrium Phase Diagram ◽  
Compressive Yield Strength ◽  
X Ray ◽  
Fine Grained ◽  
Equilibrium Phases

The phase and microstructure formation as well as mechanical properties of the rapidly solidified Mg67Ag33 (at. %) alloy were investigated. Owing to kinetic constraints effective during rapid cooling, the formation of equilibrium phases is suppressed. Instead, the microstructure is mainly composed of oversaturated hexagonal closest packed Mg-based dendrites surrounded by a mixture of phases, as probed by X-ray diffraction, electron microscopy and energy dispersive X-ray spectroscopy. A possible non-equilibrium phase diagram is suggested. Mainly because of the fine-grained dendritic and interdendritic microstructure, the material shows appreciable mechanical properties, such as a compressive yield strength and Young’s modulus of 245 ± 5 MPa and 63 ± 2 GPa, respectively. Due to this low Young’s modulus, the Mg67Ag33 alloy has potential for usage as biomaterial and challenges ahead, such as biomechanical compatibility, biodegradability and antibacterial properties are outlined.

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