<p>In view of the important applications of carbides and carbo-nitrides of transition metals in the heat-resistant and hard materials industries, the thermodynamic activities of Cr and Mn in the Cr-C, Fe-Cr-C, Mn-Ni-C and Mn-Ni-C-N systems have been studied in the present work by the use of the galvanic cell technique. CaF₂single crystals were used as the solid electrolyte. The phase relationships in selected regions of the systems in question were investigated by the use of the equilibration technique. The phase compositions and microstructures of the alloys were analysed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).</p><p>In the Cr-C system, the Gibbs energy of formation of Cr3C2 were obtained from ElectroMotive Force (EMF) measurements conducted in the temperature range 950-1150 K. The values of the enthalpy of formation of Cr₃C₂ were evaluated by the third-law method. The ground-state energy of the hypothetic end-member compound CrC3, in the bcc structure at 0 K, was calculated by use of the Ab-initio method. Based on the obtained results the Cr-C system was reassessed by use of the CALPHAD approach.</p><p>In the Fe-Cr-C system, 16 different alloys were quenched at 1223 K and their equilibrium phases identified by XRD. The experimental results show that the substitution of Cr by Fe in the (Cr,Fe)₇C₃ carbide changes the lattice parameters of the phase. A slight decrease of the lattice parameters with an increase in the Fe content was established. The lattice parameters of the γ-phase in the Fe-Cr solid solution did also show a decrease with an increase of the Fe content. The activities of chromium in Fe-Cr-C alloys were investigated in the temperature range 940-1155 K. The activity of chromium decreases with an increase in the Fe content when the ratio of C/(Cr+C) was constant. It was also established that the activity of chromium decreases with an increase of the carbon content when the iron content was constant. The experimental results obtained were compared with the data calculated by use of the Thermo-Calc software. </p><p>In the Mn-Ni-C system the phase relationships were investigated at 1073 K as well as at 1223 K. The experimental results obtained showed that the site fraction of Ni in the metallic sublattice of the carbides M₂₃C₆, M₇C₃ and M₅C₂ (M=Mn and Ni) was quite low (approximately 2~3 percent). The activities of manganese in Mn-Ni-C alloys were investigated in the temperature range 940-1165 K. The three-phase region γ/M₇C₃/graphite was partly constructed at 1073 K. </p><p>In the Mn-Ni-C-N system, nitrogen was introduced into Mn-Ni-C alloys by equilibrating with N2 gas. It was established that the solubility of nitrogen in the investigated alloys was effected by the carbon content, and that a (Mn,Ni)₄(N,C) compound was formed in the nitrided alloys. EMF measurements were performed on Mn-Ni-C-N alloys in the temperature interval 940-1127 K. The addition of nitrogen to Mn-Ni-C alloys was found to decrease the activity of manganese. The negative effect of nitrogen on the activity of manganese was found to decrease as the carbon content increased.</p><p><b>Keywords:</b> Thermodynamic activity; Galvanic cell technique; Transition metal carbides; Transition metal nitrides; Phase equilibrium; Thermodynamics; Differential thermal analysis; Scanning electron microscopy; Transmission electron microscopy; Ab-initio calculations; CALPHAD approach;</p>

Thermoelectric materials are playing a larger role in the global effort to develop diverse, efficient, and sustainable energy technologies: primarily through power-generating thermoelectric modules. The principal components of thermoelectric modules are solid-state thermoelectric materials – typically heavily doped semiconductors – that convert heat directly into electricity. However, this conversion efficiency is too low to supplant traditional energy technologies – severely limiting the distribution of clean and sustainable thermoelectric energy technologies. Efforts to enhance thermoelectric efficiency, which have been underway for decades, have been slow to realize appreciable gains in thermoelectric efficiency. However, a key advance in improving efficiency – the New Paradigm in thermoelectric material research – has been the development of thermoelectric nanocomposites. Thermoelectric nanocomposites show improved efficiency; however, they are often synthesized from highly toxic elements via energetically intense and costly synthesis procedures. Therefore, this research focuses on the discovery and development of a novel procedure for synthesizing thermoelectric nanocomposites – attrition enhanced nanocomposite synthesis – from open cage-like skutterudite-based materials. With further optimization, high-performance power-generating thermoelectric materials can be produced via this technique. Therefore, attrition-enhanced nanocomposite synthesis may play a small, though instrumental, role in achieving sustainable electrical power. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from Jan. 6, 2012 - Jan. 6, 2013

This thesis analyses long term and short term environmental effects on geothermal power plant performance and discusses adaptive ways to improve performance. Mokai 1 geothermal power plant has been used as a case study for this investigation. Mokai 1 is a combined cycle plant where the binary cycles are air-cooled. The plant performance of an air-cooled binary cycle geothermal power plant is dependent on the environment (resource characteristics as well as weather conditions). For modelling such a power plant, two time scales are of interest: the yearly basis for aggregate plant performance for design and operations; and the daily basis for hourly plant performances for an accurate dispatch prediction. Adaptive methodology for long term performance improvement has been introduced in this work which would save money and effort in the future by keeping the provisions to adapt to changes in resource characteristics based on geothermal reservoir modelling. The investigation was carried out using a steady state computer simulator of Mokai 1 geothermal power plant. The steady sate simulator was built specifically for this work. The deviation in performance of various components is less than 5% compared to the original plant design. The model is very generic and it can be used for other plants with simple adaptation or can be used for future plant design. One of the main contributions of this work is an iterative method for modelling the environmental effect on short term performance on the air-cooled organic Rankine cycle. The ambient temperature is identified as the most influencing parameter on short term performance which influences the performance of the whole cycle in two ways. Firstly, by changing the equilibrium pressure inside the condenser, the turbine outlet pressure changes and hence, the turbine pressure ratio also changes. The turbine pressure ratio is a major parameter determining power generated by a turbine; therefore, the plant output is affected. Secondly, by changing the condenser outlet temperature with the ambient temperature, the pump inlet and outlet condition and consequently vaporizer equilibrium temperature and pressure are influenced. The developed method sought the equilibrium conditions of both condenser and vaporizer iteratively. In short, ORC cycle shifts on the T-s plane depending on the ambient temperature. This method iteratively seeks the shifted ORC on the T,s plane. Two case studies have been carried out to demonstrate the method. The developed method shows robustness and converges exponentially. The model is effective for cycles that use saturated vapour as well as superheated vapour. The model essentially assumes steady state operation of the power cycle. The possible unit time where this model can be applied is bounded by the time required by a system to come into steady state. The saturated vapour cycle yielded average error 4.20% with maximum error 9.25% and the superheated vapour cycle yielded average error 2.12% with maximum error 5.60%. The main advantage of the developed method is that it requires a minimum number of inputs: condenser (p,T), vaporizer (p,T), condenser heat load, turbine efficiency (overall), pump work and the extremum conditions of all the components. These inputs should represent typical operating conditions of a plant. The model can predict the appropriate plant performance depending on the system heat input (geothermal fluid flow in this case) and the heat sink temperature. As the method is based on basic thermodynamics rather than empirical or semi-empirical approaches, this method is widely applicable. The main focus of this work is on the ORC but the developed method is applicable to any closed Rankine cycle. In addition, application of the developed iterative method to predict plant performance based on mean yearly weather data is also discussed in the thesis. Water-augmented cooling system and optimization of plant operating point parameters have been proposed as adaptive measures to improve short term performance. Developed iterative method has been used for the short term performance analysis. The water-augmented cooling system is specifically suitable to mitigate the reduced power output during the summer. The simulated average gain in power during the summer (Jan, Feb, Nov and Dec) of an ORC of Mokai 1 geothermal power plant by incorporating a water-augmented cooling system was 2.3% and the average gain for the whole year was 1.6% based on the weather data of Taupo for the year 2005. A cost benefit analysis showed that water-augmented cooling system is more economical compared to other alternative renewable energies considered to meet summer peak demand. From the green house gas emissions perspective, water-augmented cooling is a better option than the gas fired peaking plants. Adaptive approach for short term performance improvement by optimizing operating point parameters of an air-cooled binary cycle has huge potential with possible maximum improvement in power output by about 50%. The optimization takes in to account the effects of the geothermal resource characteristics and the weather conditions. The optimization is achieved by manipulating cycle mass flow rate and vaporizer equilibrium condition. Further study on the optimizing operating points to achieve improved short term performance has been recommended for future work.

No description available.

CALPHAD (CALculation of PHAse Diagrams) denotes the methodology used to assess thermodynamic data based on experiments as well as on first principles calculations. Essential for this method is the coupling of phase diagram and thermodynamic properties. It has been widely and successfully applied for decades in the field of materials science and engineering. Nevertheless, some shortcomings of the existing thermodynamic databases call for updated descriptions with improved thermodynamic modeling from unary, binary to ternary and higher-order systems. This thesis attempts to pioneer the development of a new generation of CALPHAD databases taking C-Co-Cr alloys with subsystems, unaries and binaries, as example. The present modeling and assessment work not only validate the new models applied in the development of the next, the 3rd, generation database, but also result in improved descriptions in a wider temperature range.In this 3rd generation database, thermodynamic descriptions are valid from 0 K up to high temperatures above liquidus. The Einstein model, rather than the polynomial basis functions used in the previous 2nd generation database, is applied to model the harmonic lattice vibration contribution to the heat capacity of condensed phases at low temperatures. In addition, terms describing the electronic excitations and anharmonic lattice vibrations, as well as the magnetic contribution, are added. A generalized two-state model is employed for the liquid phase to describe the gradual transition from the liquid to amorphous state. A revised magnetic model is adopted accounting for both the ferromagnetic and anti-ferromagnetic states explicitly. A newly suggested method to avoid violating the 3rd law of thermodynamics is adopted for e.g. stoichiometric phases. However, there is still some concern as Nernst’s heat theorem which states that 𝑑𝐶𝑃/𝑑𝑇 is zero at 0 K is not obeyed. All solution phases are modelled within the framework of the compound energy formalism (CEF).The task of the thesis is to construct an updated self-consistent thermodynamic description of the C-Co-Cr system for the third generation CALPHAD databases. The improvement is significant from a modeling point of view when compared to the second generation database. A good agreement between the calculated thermodynamic properties and the experimental data is achieved. The reliability of the extrapolations of unary and binary systems into higher order systems is demonstrated. / <p>QC 20170529</p>

This thesis is a theoretical study of configurational disorder in icosahedral boron-rich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of efficiently modeling configurational disorder in icosahedral boron-rich solids, whiles the thermodynamic stability as well as the properties of the configurationally disordered icosahedral boron-rich solids, modeled from the SA-SQS method, can be directly investigated, using the density functional theory (DFT). In case of boron carbide, especially B4C and B13C2 compositions, the SA-SQS method is used for modeling configurational disorder, arising from a high concentration of low-energy B/C substitutional defects. The results, obtained from the DFT-based calculations, demonstrate that configurational disorder of B and C atoms in boron carbide is not only thermodynamically favored at high temperature, but it also plays an important role in altering the properties of boron carbide − for example, restoration of higher rhombohedral symmetry of B4C, a metal-to-nonmetal transition and a drastic increase in the elastic moduli of B13C2. The configurational disorder can also explain large discrepancies, regarding the proper- ties of boron carbide, between experiments and previous theoretical calculations, having been a long standing controversial issue in the field of icosahedral boron- rich solids, as the calculated properties of the disordered boron carbides are found to be in qualitatively good agreement with those, observed in experiments. In order to investigate the configurational evolution of B4C as a function of temperature, beyond the SA-SQS level, a brute-force cluster-expansion method in combination with Monte Carlo simulations is implemented. The results demonstrate that configurational disorder in B4C indeed essentially takes place within the icosahedra in a way that justifies the focus on lowenergy defect patterns of the superatom picture. The investigation of the thermodynamic stability of icosahedral carbon-rich boron carbides beyond the believed solubility limit of carbon (20 at.% C) demonstrates that, apart from B4C generally addressed in the literature, B2.5C represented by B10Cp2(CC) is predicted to be thermodynamically stable with respect to B4C as well as pure boron and carbon under high pressure, ranging between 40 and 67 GPa, and also at elevated temperature. B2.5C is expected to be metastable at ambient pressure, as indicated by its dynamical and mechanical stabilities at 0 GPa. A possible synthesis route of B2.5C and a fingerprint for its characterization from the simulations of x-ray powder diffraction pattern are suggested. Besides modeling configurational disorder in boron carbide, the SA-SQS method also opens up for theoretical studies of new alloys between different icosahedral boron-rich solids − for example, (B6O)1−x(B13C2)x and B12(As1−xPx)2. As for the pseudo-binary (B6O)1−x(B13C2)x alloy, it is predicted to display a miscibility gap resulting in B6O-rich and either ordered or disordered B13C2-rich domains for intermediate global compositions at all temperatures up to melting points of the materials. However, some intermixing of B6O and B13C2 to form solid solutions is also predicted at high temperature. A noticeable mutual solubility of icosahedral B12As2 and B12P2 in each other to form B12(As1−xPx)2 disordered alloy is predicted even at room temperature, and a complete closure of a pseudo-binary miscibility gap is achieved at around 900 K. Apart from B12(As1−xPx)2, the thermodynamic stability of other compounds and alloys in the ternary B-As-P system is also investigated. For the binary B-As system, zincblende BAs is found to be thermodynamically unstable with respect to icosahedral B12As2 and gray arsenic at 0 K and increasingly so at higher temperature, indicating that BAs may merely exist as a metastable phase. This is in contrast to the binary B-P system, in which zinc-blende BP and icosahedral B12P2 are both predicted to be stable. Owing to the instability of BAs with respect to B12As2 and gray arsenic, only a tiny amount of BAs is predicted to be able to dissolve in BP to form BAs1−xPx disordered alloy at elevated temperature. For example, less than 5% BAs can dissolve in BP at 1000 K. As for the binary As-P system, As1−xPx disordered alloys are predicted at elevated temperature − for example, a disordered solid solution of up to ∼75% As in black phosphorus as well as a small solubility of ∼1% P in gray arsenic at 750 K, together with the presence of miscibility gaps. The thermodynamic stability of three different compositions of α-rhombohedral boron-like boron subnitride, having been proposed so far in the literature, is investigated. Those are, B6N, B13N2, and B38N6, represented respectively by B12(N-N), B12(NBN), and [B12(N-N)]0.33[B12(NBN)]0.67. It is found that, out of these sub- nitrides, only B38N6 is thermodynamically stable from 0 GPa up to ∼7.5 GPa, depending on the temperature, and is thus concluded as a stable composition of α-rhombohedral boron-like boron subnitride.

La thèse porte sur la modélisation de la transformation de l'austénite en ferrite dans les aciers en mettant l'accent sur les conditions thermodynamiques et cinétiques aux interfaces alpha/gamma en cours de croissance de la ferrite. Dans une première partie, la thèse se concentre sur la description des équilibres thermodynamiques entre alpha et gamma à l'aide de la méthode CalPhad. Nous avons développé un nouvel algorithme hybride combinant la construction d'une enveloppe convexe avec la méthode classique de Newton-Raphson. Nous montrons ses possibilités pour des aciers ternaire Fe-C-Cr et quaternaire Fe-C-Cr-Mo dans des cas particulièrement difficiles. Dans un second chapitre, un modèle à interface épaisse a été développé. Il permet de prédire l'ensemble du spectre des conditions à l'interface alpha/gamma au cours de la croissance de la ferrite, de l'équilibre complet au paraéquilibre avec des cas intermédiaires des plus intéressants. Nous montrons que de nombreux régimes cinétiques particuliers dans les systèmes Fe-C-X peuvent être prévus avec un minimum de paramètres d'ajustement, principalement le rapport entre les diffusivités de l'élément substitutionnel dans l'interface épaisse et dans le volume d'austénite. Le troisième chapitre porte sur l'étude d'un modèle de champ de phase. Une analyse approfondie des conditions à l'interface données par le modèle est réalisée en utilisant la technique des développements asymptotiques. En utilisant les connaissances fournies par cette analyse, le rôle de la mobilité intrinsèque d'interface sur la cinétique et les régimes de croissance est étudié, à la fois dans le cas simple d'alliages binaires Fe-C et dans le cas plus complexe d'alliages Fe-C-Mn / Transformation in steels focusing on the thermodynamic and kinetics conditions at the alpha/gamma interfaces during the ferrite growth. The first chapter deals with the determination of thermodynamic equilibria between alpha and gamma with CalPhad thermodynamic description. We have developed a new hybrid algorithm combining the construction of a convex hull to the more classical Newton-Raphson method to compute two phase equilibria in multicomponent alloys with two sublattices. Its capabilities are demonstrated on ternary Fe-C-Cr and quaternary Fe-C-Cr-Mo steels. In the second chapter, we present a thick interface model aiming to predict the whole spectrum of conditions at an alpha/gamma interface during ferrite growth, from full equilibrium to paraequilibrium with intermediate cases as the most interesting feature. The model, despite its numerous simplifying assumptions to facilitate its numerical implementation, allows to predict some peculiar kinetics in Fe-C-X systems with a minimum of fitting parameters, mainly the ratio between the diffusivities of the substitutional element inside the thick interface and in bulk austenite. The third chapter deals with the phase field model of austenite to ferrite transformation in steels. A thorough analysis on the conditions at the interface has been performed using the technique of matched asymptotic expansions. Special attention is given to clarify the role of the interface mobility on the growth regimes both in simple Fe-C alloys and in more complex Fe-C-Mn alloys

Le procédé de précipitation du peroxyde d'uranium en lit fluidisé breveté par AREVA est actuellement testé à l'échelle pilote sur différents sites miniers en vue d'applications industrielles à court terme. Le yellow cake formé par ce procédé a des qualités très intéressantes en termes de densité, granulométrie et morphologie pour la manipulation et le transport. De plus, le faible taux d'impuretés présents dans le peroxyde d'uranium est un atout important pour la suite du procédé de fabrication du combustible. L'objectif de ce travail est de déterminer la thermodynamique ainsi que les cinétiques de nucléation primaire et de croissance cristalline qui régissent la précipitation du peroxyde d'uranium en vue d'une modélisation globale permettant de simuler le comportement du système. Afin de déterminer la solubilité du peroxyde d'uranium sur une large gamme de conditions opératoires correspondante aux conditions du procédé industriel, un modèle de solubilité a été développé et optimisé à l'aide de mesures expérimentales. Dans le cadre de cette étude, le produit de solubilité a été identifié ce qui a permis la mise en équation et le calcul de la sursaturation, force motrice de la précipitation qu'il est indispensable de connaitre pour l'étude des cinétiques de nucléation et de croissance. Les nucléations primaires sont étudiées par une approche phénoménologique qui met en oeuvre une méthode développée par Bertrand-Andrieu basée sur l'utilisation d'un appareil permettant un micromélange très rapide (~1ms) des réactifs. La cinétique de nucléation primaire du peroxyde d'uranium suit la loi classique de Volmer et Weber. De plus il est démontré que la nucléation primaire est fonction de la concentration de sulfate, la loi correspondante intègre alors cette dépendance via le terme BN lié à la tension interfaciale et ainsi à la quantité de sulfate absorbée. La cinétique de croissance est de même déterminer par une approche phénoménologique. Au vue de la production d'ions H+ au cours de la réaction de précipitation, l'étude expérimentale de la croissance cristalline est effectuée par suivi pH-métrique. Étant indépendante de la vitesse d'agitation, la croissance est contrôlée par l'intégration au réseau cristallin selon un mécanisme en spirale. Il est démontré que la loi de croissance du peroxyde d'uranium est d'ordre un vis-à-vis de la sursaturation, le paramètre cinétique kg étant dépendant de la concentration de sulfate et du pH, une loi empirique fonction des conditions expérimentales est alors proposée pour ce paramètre / The uranium peroxide precipitation in fluidised bed patented by AREVA is currently tested on pilot scale reactor on different mine sites for industrial applications in the short term. The yellow cake produced on this way has very interesting qualities in terms of density, particle size and morphology for handing and transport. In addition, the low level of impurities present in the uranium peroxide is an important advantage for the rest of the manufacturing process fuel. The objective of this work is to determine the thermodynamics and kinetics of primary nucleation and crystal growth governing the uranium peroxide precipitation for a global modelling to stimulate the system behaviour. In order to determine the uranium peroxide solubility over a wide range of operating conditions corresponding to the industrial process conditions, a solubility model has been developed and optimized using experimental measurements. In this study, the solubility product has been identified which allows the calculation of the supersaturation, driving force of the precipitation which is an essential parameter to know in order to study the nucleation and crystal growth kinetics. The primary nucleation is investigated by a phenomenological approach which implements a method developed by Bertrand-Andrieu based on the use of a very fast reagents micromixing device (~1ms). Uranium peroxide primary nucleation kinetics follows the Volmer and Weber law. Furthermore it is shown that the primary nucleation depends on the sulphate concentration, the corresponding law incorporates this link with the BN term related to the interfacial tension and thus the quantity of sulphate absorbed. Crystal growth kinetics is also determined by a phenomenological approach. Due to the hydrogen ion production during the precipitation reaction, the crystal growth experimental study is performed by a pH-metric monitoring. Independent of the impeller speed, crystal growth is surface integration controlled with a spiral mechanism. It is shown that the uranium peroxide crystal growth law is first order with respect to the supersaturation. The kinetic parameter kg is dependent on pH and sulphate concentration, an empirical law function of the experimental conditions is then proposed for this parameter

To reduce the greenhouse effect, the use of renewable fuel has to be increased. As renewable fuel has different characteristics compared to fossil fuel regarding content of trace metals, alkali, chlorine and sulphur, the corrosion characteristics in high temperature energy processes have to be evaluated. This thesis concerns high temperature corrosion in the superheater region of a boiler and the syngas cooler area of a gasifier. For the superheater region, laboratory exposures were performed. The methods included a salt dip exposure, where samples were dipped in an equimolar solution of ZnCl2 and KCl, and two salt bed exposures with different chlorine concentrations, 10 and 20 wt%. Ranking of the materials showed that a Ni content above 10 wt% and Cr above 20 wt% reduced corrosion rates in the salt dip and in the 10% Cl salt bed exposure. For exposure in the 20% Cl bed, even higher alloying was needed. An alumina forming austenitic steel showed future potential in sulphidising-chlorinating environments. For the gasifier region, the effect of HCl in a simulated gasifier atmosphere was studied and also samples exposed in the syngas section of a biomass gasifier were investigated. Metal loss was low for all exposures and it was observed that chlorine had minor influence. For the plant exposed samples, a difference compared to that reported for coal gasifiers was the absence of FeS for the lowest alloyed steel. Instead, a deposit with pronounced content of Zn, Ca, S and O was present on the surface. Zinc was suggested to mitigate corrosion. Thermodynamic modelling was used to explain phases present and to predict the nitridation behaviour of an alumina forming austenitic steel. Equilibrium and kinetic modelling of the nitridation showed good coherence with the observed microstructures. However, the kinetic modelling resulted in larger nitridation depths than observed experimentally which was attributed to the presence of a thin oxide layer on the surface of the samples. / <p>QC 20160510</p>

The main aim of this thesis was to design and develop new Aluminium based compositionally complex alloys (CCAs) using the high entropy alloy (HEA) concept, and to understand their evolution of microstructures during casting and also after the secondary process which is heat-treatment, and finally to evaluate their subsequent mechanical properties. Prior to the development of alloys, a computational technique ThermoCalc was used which helped in understanding the phase formation in various results. Use of thermodynamic physical parameters for predicting the stability of single-phase fields was done to assess their validity in predicting the compositional regions of the alloys developed. The first alloy developed is Al73.6Mg18Ni1.5Ti1.9Zr1Zn4 in at% (NiTiZrZn) CCA. The microstructure consists of the FCC as a primary phase with ~49% volume fraction along with β-AlMg and intermetallic (IM) phases including Al3Ni, Al3Ti, and Al3Zr. After casting, the microstructure showed some presence of eutectic structures. The Al3Ti, and Al3Zr IM phases seemed to precipitate early which led to less homogenization of Ti and Zr, causing deviation in the amount of these elements in the matrix. Further, the CCA was heat-treated at 375 oC for 24hrs and 48hrs and the evolution of microstructure along with its hardness and phase transformation characterisation was investigated. The second developed alloy was quaternary Al65.65Mg21.39Ag10.02Ni2.94 in at% (AgNi) CCA. In the as-cast state, the main phase (matrix) was FCC with ~64 % volume fraction along with BCC, β-AlMg and Al3Ni IM phases. There was a good level homogenization of all elements in the alloy. They were further heat- treated at 400 oC for 24 hrs and 48 hrs and were studied for any change in microstructure along with its hardness and thermal stability. This CCA had the highest hardness value from all developed CCAs. Lastly, in order to check how Ni affects the microstructure and properties of (AgNi) CCA, a ternary Al67.2Mg22.09Ag10.7 in at% (Ag) CCA was developed. The composition was kept such that it is exactly 97% by excluding the Ni. During the development of this alloy, the cast was cooled in two ways first being the normal cooled just like other CCAs and second being a fast cooling method. Both of these alloys consists of the FCC phase as a primary phase with 72% volume fraction along with BCC and β-AlMg. Both of them were also heat treated at 400 oC for 24 hrs and 48 hrs to evaluate any changes in microstructure and also to assess its hardness and thermal stability.