Phase equilibria studies of two ternary systems, the vanadium rhodium-silicon system and the niobium-rhodium-silicon system, were made to obtain information about the formation of the Cr₃O-type structure in these systems. All samples had compositions in the . vicinity of the stoichiometric Cr₃O composition line and were prepared by powder metallurgy techniques. The compacts were then arc-melted, given a homogenization anneal, and examined by x-ray diffraction. Complete solid solubility of silicon for rhodium was found across the V-Rh-Si system in the Cr₃O-type structure. A large range of vanadium compositions for the formation of the Cr₃O-type structure in the V-Rh-Si system was also found. A minimum lattice parameter was found for samples closely approximating the stoichiometric Cr₃O composition in the V-Rh-si system. Either an increase or a decrease in vanadium composition from stoichiometry caused an increase in the lattice parameter of the Cr₃O-type structure formed. No solid solubility of silicon for rhodium was found in the niobium-rhodium-silicon system. Apparently the only Cr₃O-type structure which forms in the Nb-Rh-Si system is of' the stoichiometric composition Nb₃Rh. / Master of Science

1. From a study of the system salicylic acid-biphenyl it was concluded that there was no compound formation in the system. The solution is very nearly ideal, having an eutectic temperature of 67.6℃ at a mole fraction of .903 for the biphenyl. 2. The system salicylic acid-diphenylamine was studied and no compound formation was found to be present. The system and no compound formation was found to be present. The system is not as ideal as the salicylic acid-biphenyl system, but follows the ideal solution curve fairly well. The system has an eutectic temperature of 48.5℃ at .926 mole fraction of diphenylamine. / M.S.

Computer simulations of the growth of binary alloy thin films in two and three dimensions were performed using an extension of the Solid on Solid model. Snapshots for a range of interactions and diffusion rates are presented and critically compared to experiment. A wide variety of distinct phases is identified and their growth conditions analyzed. These findings are summarized in a phase diagram. In addition, a fractal analysis of the domains is performed. It is found that for negative interactions the islands are two-dimensional, while for positive interactions, regardless of diffusion rate, a fractal dimension of 1.78 is obtained. / by Mark R. Bouwens. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

This thesis describes Monte-Carlo computer simulations of binary alloys, with comparisons between small angle neutron scattering (SANS) data, and numerically integrated solutions to the Cahn-Hilliard-Cook (CHC) equation. Elementary theories for droplet growth are also compared with computer simulated data. Monte-Carlo dynamical algorithms are investigated in detail, with special regard for universal dynamical times. The computer simulated systems are Fourier transformed to yield partial structure functions which are compared with SANS data for the binary Iron-Chromium system. A relation between real time and simulation time is found. Cluster statistics are measured in the simulated systems, and compared to droplet formation in the Copper-Cobalt system. Some scattering data for the complex steel PE16 is also discussed. The characterisation of domain size and its growth with time are investigated, and scaling laws fitted to real and simulated data. The simple scaling law of Lifshitz and Slyozov is found to be inadequate, and corrections such as those suggested by Huse, are necessary. Scaling behaviour is studied for the low-concentration nucleation regime and the high-concentration spinodal-decomposition regime. The need for multi-scaling is also considered. The effect of noise and fluctuations in the simulations is considered in the MonteCarlo model, a cellular-automaton (CA) model and in the Cahn-Billiard-Cook equation. The Cook noise term in the CHC equation is found to be important for correct growth scaling properties.

Thesis (Ph. D.)--State University of New York at Binghamton, Mechanical Engineering Department, 2005. / Includes bibliographical references (leaves 149-155).

Thesis (Ph. D.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 238-246.

Thesis (Ph. D.)--University of Chicago, Dept. of Chemistry, March 1999. / Includes bibliographical references. Also available on the Internet.

A series of compositions across the niobium-rhodium- silicon ternary diagram from Nb₃Rh to 75 atomic percent niobium-25 percent silicon, were prepared by arc-melting compacts of high-purity powders. Both x-ray diffractometer and camera techniques were used to analyze the resulting structures. No measurable amount of silicon was found to substitute for rhodium in the Nb₃Rh structure. The 75 percent niobium-25 atomic percent silicon composition contains niobium plus an unidentified phase assumed to be Nb₅Si₃. The Nb-Rh sigma phase extends into the ternary system to at least 10 atomic percent silicon. All ternary alloys investigated contained three phases. These phases were one or more unidentified phases combined with either A₃B or sigma or both. / M.S.

No description available.

The current study focuses on phase stability and evolution in the titanium-zinc titanium-copper and titanium-antimony systems. The study utilized the Laser Engineering Net Shaping (LENS™) processing technique to deposit compositionally graded samples of three binary system in order to allow the assessment of phase stability and evolution as a function of composition and temperature the material is subjected to. Through LENS™ processing it was possible to create graded samples from Ti-xSb (up to 13wt%) and Ti-xCu (up to 16wt%). The LENS™ deposited gradient were solutionized, and step quenched to specific aging temperature, and the resulting microstructures and phase were characterized utilizing XRD, EDS, SEM, FIB and TEM. The Ti-Zn system proved incapable of being LENS™ deposited due to the low vaporization temperature of Zn; however, a novel processing approach was developed to drip liquid Zn onto Ti powder at temperatures above β transus temperature of Ti (882 ◦C) and below the vaporization temperature of Zn (907 ◦C). The product of this processing technique was characterized in a similar way as the graded LENS™ depositions. From measurements performed on Ti-Sb it seems that Sb could be a potential α stabilizer in Ti due to the presence of a mostly homogeneous α grains throughout the gradient; however, from XRD it can be understood that a titanium antimonide phase is present. From results obtained from the Ti-Zn samples, it can be surmised that the eutectoid reaction seems to be active, i.e. The eutectoid reaction is kinetically fast, as concluded by the presence of pearlitic structures. Finally, for the Ti-Cu system this work has been attempted to prove or disprove the existence of the Ti3Cu through the use of XRD and TEM SAD patterns. From XRD spectra collected there are peaks belonging to the Ti3Cu orthorhombic phase along with Ti2Cu and α-Ti phase. In addition to the Ti-Cu system displayed structures associated with divorced eutectoid decomposition mechanism, and at low undercooling seems to be prone to forming solid state dendrites.