Drug solid solutions – a method for tuning phase transformations

CrystEngComm ◽  
2014 ◽  
Vol 16 (26) ◽  
pp. 5827-5831 ◽  
Author(s):  
Amit Delori ◽  
Pauline Maclure ◽  
Rajni M. Bhardwaj ◽  
Andrea Johnston ◽  
Alastair J. Florence ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Transformations ◽  
Solid Solutions ◽  
Transformation Temperatures

Tuning phase transformation temperatures through the use of solid solutions.

Study of Thermo-Physical Properties of Selected Nickel-Based Superalloys With Use of DTA Method

2012 ◽  
Author(s):  
Jana Dobrovska ◽  
Simona Zla ◽  
Frantisek Kavicka ◽  
Bedrich Smetana ◽  
Vlastimil Vodarek
Keyword(s):  
Phase Transformation ◽  
Physical Properties ◽  
Phase Transformations ◽  
Solidus Temperature ◽  
Experimental System ◽  
Reaction Scheme ◽  
Transformation Temperatures ◽  
Heating And Cooling ◽  
Temperature Heating ◽  
Thermo Physical Properties

The presented paper deals with study of thermo-physical properties of cast complex alloyed nickel based superalloys IN713LC, IN738LC and IN792-5A. In this work the technique of Differential Thermal Analysis was selected for acquisition and comparison of the phase transformation temperatures. The samples taken from superalloys in as received state were analysed at heating and cooling rates of 1, 5, 10, and 20 K/min using the experimental system Setaram SETSYS 18TM. Moreover, the transformation temperatures for zero heating/cooling rate were calculated. Based on a comparison of these temperatures it is possible to make the following conclusions: (i) The alloy IN792-5A has the highest temperature of solubility of the strengthening phase γ′ (1235°C); (ii) the highest liquidus temperature (heating) obtained by extrapolation was found in the alloy IN713LC (1349°C), the lowest solidus temperature (heating) was found for the alloy IN738LC (1212°C); (iii) At cooling an undercooling occurred in all alloys. In general it may be stated that the biggest under-cooling (TS, 47°C) was recorded in the alloy IN792 5A; (iv) The width of the interval of the heat treatment window was the biggest in alloy IN713LC (44°C); (v) The alloy IN738LC is characterised by the widest interval of melting (124°C) and solidification (134°C), while the alloy IN792 5A has the narrowest interval of melting (82°C) and at the same time almost the same interval of solidification as the alloy IN738LC (129°C); (vi) The obtained phase transformation temperatures were compared with the values of phase transformations temperatures calculated on the basis of established relationships. In order to obtain more precise description of the behaviour of Ni-based superalloys, during controlled heating/cooling of the initial material (as received state) during DTA analyses, all the samples of superalloys were subjected to a phase analysis using scanning electron microscopy. The course of phase transformations, in all the studied superalloys (IN713LC, IN738LC, IN792 5A) is likely to run according to the following reaction scheme (L = melt): L ↔ γ, L ↔ γ + MC, L ↔ γ/γ′, L ↔ γ + minority phases (such as M3B2, phase η), γ ↔ γ′.

scholarly journals Phase Transformations, Magnetic Susceptibility and NEXAFS-Spectra of Cobalt-Doped Solid Solutions of Bismuth Orthoniobate

2020 ◽  
pp. 89-98
Author(s):  
Nadezhda A. Zhuk ◽  
Lubov V. Rychkova ◽  
Sergey V. Nekipelov ◽  
Boris A. Makeev
Keyword(s):  
Magnetic Susceptibility ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Electronic State ◽  
Solid Solutions ◽  
Electron State ◽  
Exchange Interactions ◽  
X Ray ◽  
Nexafs Spectroscopy ◽  
Charge States

The electron state and the nature of the exchange interactions of cobalt atoms in BiNb1-xСoxO4-δ solid solutions of triclinic and orthorhombic modifications were studied using the magnetic susceptibility and NEXAFS-spectroscopy. In order to determine the electronic state of cobalt atoms, the solid solutions and oxides of cobalt CoO, Co3O4 were studied by NEXAFS-spectroscopy. The X-ray spectroscopy and the study of the magnetic susceptibility of the solid solutions revealed the presence of the monomers and exchange-related clusters of cobalt with the Co(II) and Co(III) charge states characterized mostly by the antiferromagnetic type of exchange. The cobalt containing solid solutions allowed us to confirm the reversibility of the α↔β-BiNbO4 phase transformation

scholarly journals The Effect of Sn Addition on Zn-Al-Mg Alloy; Part I: Microstructure and Phase Composition

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5404
Author(s):  
Peter Gogola ◽  
Zuzana Gabalcová ◽  
Martin Kusý ◽  
Henrich Suchánek
Keyword(s):  
Phase Transformation ◽  
Phase Composition ◽  
Solid Solutions ◽  
Volume Content ◽  
Intermetallic Phases ◽  
Mg Alloy ◽  
Transformation Temperatures ◽  
Mg2sn Phase ◽  
Alloy Part ◽  
Xrd Techniques

In this study, the addition of Sn on the microstructure of Zn 1.6 wt.% Al 1.6 wt.% Mg alloy was studied. Currently, the addition of Sn into Zn-Al-Mg based systems has not been investigated in detail. Both as-cast and annealed states were investigated. Phase transformation temperatures and phase composition was investigated via DSC, SEM and XRD techniques. The main phases identified in the studied alloys were η(Zn) and α(Al) solid solutions as well as Mg2Zn11, MgZn2 and Mg2Sn intermetallic phases. Addition of Sn enabled the formation of Mg2Sn phase at the expense of MgxZny phases, while the overall volume content of intermetallic phases is decreasing. Annealing did not change the phase composition in a significant way, but higher Sn content allowed more effective spheroidization and agglomeration of individual phase particles.

The DSC Investigation on Phase Transformations of Directionally Solidified (DS) and Powder Metallurgy (PM) Ni-Base Superalloys

2018 ◽  
Vol 941 ◽  
pp. 1035-1040
Author(s):  
Liang Zheng ◽  
Yu Feng Liu ◽  
Michael J. Gorley ◽  
Zu Liang Hong ◽  
Sarah Day ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Transformation ◽  
Powder Metallurgy ◽  
Phase Change ◽  
Phase Transformations ◽  
Cooling Rate ◽  
Cooling Curves ◽  
Directionally Solidified ◽  
Transformation Temperatures ◽  
Heating And Cooling

The phase transformations of the directionally solidified (DS) and powder metallurgy (PM) Ni-base superalloys were investigated by JMatPro, synchrotron XRD (SXRD) and differential scanning calorimetry (DSC). The minor phases, such as MC, eutectic γ′ and Ni5Hf, and γ matrix with secondary γ′ existed in as-cast microstructure of DS DZ22. However, only γ matrix was found in PM625 alloy powders. The phase change in both heating (melting) and cooling (solidification) process was investigated by DSC on DZ22 test bar and PM625 alloy powders respectively. The DSC experiment with different heating/cooling rates (5-40°C/min) was performed on DS superalloy DZ22. The results indicated that the heating/cooling rate had obvious effect on the DSC results of the phase transformation temperatures of liquidus, MC carbides, solidus, eutectic (γ+γ′) and secondary γ′. The heating and cooling DSC curves shifted to high and low temperature direction respectively, accompanied by the heating/cooling rate increased. However, the average values of specific peaks of heating and cooling curves are relatively consistent which is close to the equilibrium phase change temperatures of the alloy and makes the results comparable. Besides the average value method, the liquidus temperature of the alloy (0°C/min) can also be obtained by method of linear-fit/extrapolating from 5-40°C/min heating/cooling rates or inflection point deviate from the baseline of DSC cooling curves which could minimize the heating/cooling rate effects. The DSC experiment was carried out on PM625 superalloy powders with different particle size range (0-355μm), the results indicated that the particle size had minor effect on liquidus and solidus temperatures of DSC heating curves, the differences were less than 2°C. The change in phase transformation temperatures under different heating/cooling rate should be considered for selecting the process parameter (heat treatment, HIP or casting) for manufacturing Ni-base superalloy components.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

ChemInform Abstract: PHASE TRANSFORMATIONS OF RARE EARTH DICARBIDE SOLID SOLUTIONS

1978 ◽  
Vol 9 (26) ◽  
Author(s):  
G.-Y. ADACHI ◽  
F. TONOMURA ◽  
Y. SHIBATA ◽  
J. SHIOKAWA
Keyword(s):  
Rare Earth ◽  
Phase Transformations ◽  
Solid Solutions

Calculations of Phase Transformations in Welding Simulations

2014 ◽  
Vol 611 ◽  
pp. 46-53 ◽  
Author(s):  
Ladislav Novotný ◽  
Vladimír Ivančo
Keyword(s):  
Heat Flux ◽  
Phase Transformation ◽  
Boundary Conditions ◽  
Phase Transformations ◽  
Diffusion Processes ◽  
Transient Solution ◽  
Welding Simulation

In the paper the principle of welding simulation is presented and the methods of solution of phase transformation are described. The first part characterizes elementary equations of heat transient solution, boundary conditions during welding simulation (prescribing moving heat flux, convection, radiation). The methods of phase transformations’ solution are described for diffusion processes as well as diffusionless processes.

Influence of Phase Transformations on Residual Stresses in Welded Structures

2013 ◽  
Author(s):  
R. J. Dennis ◽  
R. Kulka ◽  
O. Muransky ◽  
M. C. Smith
Keyword(s):  
Phase Transformation ◽  
Residual Stresses ◽  
Phase Transformations ◽  
Numerical Models ◽  
Material Model ◽  
Transformation Model ◽  
Austenitic Steels ◽  
Beam Specimen ◽  
Welded Structures ◽  
The Impact

A key aspect of any numerical simulation to predict welding induced residual stresses is the development and application of an appropriate material model. Often significant effort is expended characterising the thermal, physical and hardening properties including complex phenomena such as high temperature annealing. Consideration of these aspects is sufficient to produce a realistic prediction for austenitic steels, however ferritic steels are susceptible to solid state phase transformations when heated to high temperatures. On cooling a reverse transformation occurs, with an associated volume change at the isothermal transformation temperature. Although numerical models exist (e.g. Leblond) to predict the evolution of the metallurgical phases, accounting for volumetric changes, it remains a matter of debate as to the magnitude of the impact of phase transformations on residual stresses. Often phase transformations are neglected entirely. In this work a simple phase transformation model is applied to a range of welded structures with the specific aim of assessing the impact, or otherwise, of phase transformations on the magnitude and distribution of predicted residual stresses. The welded structures considered account for a range of geometries from a simple ferritic beam specimen to a thick section multi-pass weld. The outcome of this work is an improved understanding of the role of phase transformation on residual stresses and an appreciation of the circumstances in which it should be considered.

Sign in / Sign up

Export Citation Format

Share Document