Download or read book Microstructure and Property Evolution in Refractory Alloys and Weldments written by Noah Michael Kohlhorst and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a thorough study of the microstructure evolution of alloys and welds subjected to different processing conditions. The microstructure of alloys and welds are strongly influenced by processing conditions which influences the materials mechanical properties and performance. A new technique has been developed to quantify the spatial variation of grain sizes, grain shapes, and grain boundary curvatures in the fusion zone (FZ) and heat affected zone (HAZ) of welds. Very limited past work has been done to quantify many of these grain microstructure properties characterized from this technique. Trends between each microstructural feature has been captured between welds subjected to different welding parameters and post weld processing. Accruing knowledge of the microstructural trends with processing conditions has proven to be advantageous in developing correlations with various mechanical properties and advancing weld engineering. The microstructure evolution of gas tungsten arc molybdenum welds subjected to multiple weld processing conditions has been evaluated with the developed technique. Varying the heat input, welding speed, and welding technique caused noticeable to drastic changes in the FZ and HAZ grain microstructure which also influenced the materials mechanical properties. The microstructure evolution of DOP-26 GTA welds subjected to different levels of thermal exposures has also been evaluated with the developed technique. Iridium alloys are primary used in space applications and the thermal exposures simulated typical operation conditions and launch failure scenarios. Annealing causes significant changes to many grain properties in the FZ of these welds which was correlated to changes in mechanical properties. Other techniques including SEM and EBSD has been done to capture the precipitate distribution and grain texture in the weld answering questions posed from the microstructure evaluation results. Alloy design and development is critical for the new generation of iridium alloys typically used for space applications. Currently Iridium is made into DOP-26 alloyed with 0.3 wt% tungsten, 50 ppt aluminum, and 60 parts per million (ppm) thorium. The thorium actively enhances the grain boundary strength and hinders grain growth during high thermal exposures with the formation eutectic primary precipitates. There is a desire to replace thorium with cerium, a non-radioactive potentially less expensive alloying substitute with thorium which behaves like thorium in iridium. A recrystallization study with respect to cerium and thorium content in iridium alloys has been evaluated. The recrystallization behavior of a material is influenced by the nature and quantity of the alloying element which governs the final microstructure post processing. The microstructure evolution at different stages of recrystallization was evaluated by capturing the percentage recrystallized, texture, and strain. The change in recrystallization rates at various annealing temperatures with respect to cerium content has been determined from the results. Analyzing the texture provided insight to how substituting cerium influences the microstructure by means of the formation and strength (sharpness) of cubic texture and fiber textures with annealing temperature. An understanding of the recrystallization behavior with respect to alloying is critical in developing processing steps to produce desirable microstructures with the best mechanical properties.
Download or read book Evolution of Refractory Metals and Alloys written by Edward N. C. Dalder and published by Minerals, Metals, & Materials Society. This book was released on 1994 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of papers is from the 1993 TMS annual Meeting held in Denver, Colorado, February 21-25, 1993. It provides a review of the development of refractory metal alloys (those based on vanadium, columbian, niobium, tantalum, molybdenum, tungsten and rhenium) from the 1950s to the present. The technology of many of the leading researchers in this area has been recorded and preserved as a reference for current and future researchers.
Download or read book Solidification Behaviour and Microstructure Evolution of Refractory Metals based Alloys Under Rapid Solidification written by Leandro Moraes Feitosa and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Refractory Metal Alloys Metallurgy and Technology written by I. Machlin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication documents Proceedings of the Symposium on Metal lurgy and Technology of Refractory Metal Alloys, held in Washington, D.C. at the Washington Hilton Hotel on April 25-26, 1968, under sponsorship of the Refractory Metals Committee, Institute of Metals Division, of the Metallurgical Society of AIME, and the National Aeronautics and Space Administration. The Symposium presented critical reviews of selected topics in refractory metal alloys, thereby contributing to an in-depth understanding of the state-of-the-art, and establishing a base line for further research, development, and application. This Symposium is fifth in a series of conferences on refractory metals, sponsored by the Metallurgical Society of AlME. Publications issuing from the conferences are valuable technical and historical source books, tracing the evolution of refractory metals from early laboratory alloying studies to their present status as useful engineering materials. Refractory metals are arbitrarily defined by melting point. A 0 melting temperature of over 3500 F was selected as the minimum for this Symposium, thus excluding chromium and vanadium, which logically could be treated with other refractory metals in Groups VA and VIA of the periodic table. The Refractory Metals Committee is planning reviews of chromium and vanadium in subsequent conferences.
Download or read book Microstructure Evolution in the Fusion of Welding of Heat Treatable Al Cu Li Alloys written by Kuang-Hua Hou and published by . This book was released on 1994 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Fabrication History and Microstructure on the Mechanical Properties of Refractory Metals and Alloys written by Albert G. Imgram and published by . This book was released on 1963 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the present knowledge concerning the relationship among fabrication history, metallurgical structure, and the mechanical properites of the refractory metals columbium, tantalum, bolybdenum, and tungsten, and their alloys. These are the refractory metals currently reveiveing the most attention for aerospace applications, and are therefore the materials considered in this survey. The report is organized into three main sections, titled ''Fabrication'', ''Microstructure and Alloying'', and ''Interstitial Impurities''. The data presented were selected as those which best illustrate the topics discussed. Descriptions of the metaljurgical principles involved are included. Suggestions for optimizing mechanical properties by controlling metallurgical structure are made where possible. (Author).
Download or read book The Effects of Heat treating and Testing Environments on the Properties of Refractory Metals written by F. F. Schmidt and published by . This book was released on 1964 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies on the effects of heat-treating and testing environments for the refractory metals have been limited primarily to the unalloyed metals and a few alloys of columbium and molybdenum. Most of this work has relied on compositional changes as a means of assesing the effects of various environments on these materials. It has been shown that all of these materials are subject to contamination or purification in various test environments. The residual gases H2, CO(or N2), and H20, constitute the major sources of contamination when testing columbium and tantalum materials in vacua. Under the same conditions, molybdenum and molybdenum alloys containing carbon and reactive-metal additions are subject to serious decarburization. Nonreactive gaseous atmospheres also cause serious changes in material chemistry, since small quantities of noxious gases are contained in the atmosphere. Several promising methods of circumventing material chemistry changes during various longtime, high-temperature exposures are being used and/or evaluated. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Properties of Refractories written by J.P. Singh and published by Trans Tech Publications Ltd. This book was released on 1993-08-20 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: While iron and steel industries are the major users of refractory materials, applications in other areas such as power plants and waste incinerators are of growing importance. The appropriate use and maximum performance of the refractories cannot be achieved unless their interaction with the service environment is properly understood. The correlations between the microstructure of these materials and their thermochemical as well as thermomechanical properties greatly enhances this understanding.
Download or read book Microstructure Evolution and Its Effect on Fatigue Performance in Inertia Welds of Titanium and Nickel Based Alloys written by Yogiraj Urkudashau Pardhi and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Entropy Alloys written by Ghulam Yasin and published by Elsevier. This book was released on 2024-07-26 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Entropy Alloys: Design, Manufacturing, and Emerging Applications presents cutting-edge advances in the field of these materials, covering their mechanics, methods of manufacturing, and applications, all while emphasizing the link between their structure/microstructure and functional properties. The book starts with a section on the fundamentals of high-entropy alloys (HEAs), with chapters discussing their thermodynamics, subgroups (transition metal; refractory; ceramics; metallic glasses and more), physical metallurgy, and microstructural characterization. The next section features chapters which look at manufacturing processes of HEAs, such as liquid metallurgy synthesis, in-situ synthesis, additive manufacturing, machine learning, friction stir welding, and fabrication of coatings for HEAs. The final section of the book covers applications of these materials, including their use as irradiation-resistant structural materials, catalyst materials, electrode materials, HEAs for solid hydrogen storage, and more. The book is a key resource for academic researchers, grad students, and industry professionals working with HEAs across a range of disciplines and applications including aerospace, functional materials, catalyst materials, gas storage, sensing, super-conducting materials, biomedical, civil engineering, energy storage, and energy materials. - Covers the mechanics, manufacturing, and applications of functionally-oriented high-entropy alloys (HEAs) - Discusses the metallurgical composition of HEAs, their microstructural characterization, thermal stability, and how to manufacture them via powder metallurgy, additive manufacturing, and friction stir welding - Reviews applications of HEAs such as for irradiation-resistant structural materials, in biomedical settings, as catalyst materials, for solid hydrogen storage, and more
Download or read book Refractory Boride Formation and Microstructure Evolution During Solidification of Ti B and Ti Al B Alloys written by Mark Edward Hyman and published by . This book was released on 1990 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evolution of Microstructure and Mechanical Properties During Linear Friction Welding of AD730TM Ni based Superalloy written by Fatemeh Masoumi and published by . This book was released on 2018 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Mechanical Properties of Refractory Metal Alloys Formed by Field Assisted Sintering Technique FAST written by Paul Browning and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Refractory metals and their alloys are of critical importance for a large number of applications ranging from nuclear fission and fusion reactors to the defense and aerospace industries. Of the refractory metal alloys, tungsten, tantalum, and molybdenum alloys are dominant in both commercial and defense applications. Unfortunately, due to their high melting temperatures and relatively poor sinterability, formation of high-density components of these alloys is difficult, requiring either the use of time-consuming and expensive techniques such as hot isostatic pressing or post-processing such as hot extrusion and annealing to produce components acceptable for structural use. Furthermore, as components of these compounds are generally by their very nature used at elevated operating temperatures, they frequently experience failure due to recrystallization, grain growth, and creep.Field Assisted Sintering Technique (FAST), also commonly referred to as spark plasma sintering (SPS) or pulsed electric current sintering (PECS) is a promising method for formation of dense compacts of traditionally difficult to sinter materials. FAST uses a combination of elevated temperatures, pressures, and the application of an electric field to rapidly sinter components over the course of several minutes to hours. FAST is an excellent technique for rapid production of refractory alloys, as it produces near net-shaped components featuring equiaxed grain structures. As FASTs uses rapid heating and cooling rates, it is also capable of producing dense components of much finer grain sizes in comparison to traditional sintering techniques.This dissertation explores the use of FAST and alloying additions to produce refractory metal alloys featuring improved mechanical properties over current commercially available materials. Work begins by exploring the room and ultra-high temperature mechanical properties of a series of tungsten alloys (Chapter 3) attempting to make use of Ta and TiC alloying additions. W-TiC alloys are found to be promising for high-strength applications where ductility is less of an issue, and display substantial resistance to grain growth at temperatures up to1927 C (3500 F). This strengthening effect was found to be lost upon testing at 2204 C (4000 F). In contrast, a tested W-10vol%Ta alloy was found to display high strength and ductility at temperatures of 1649 C (3000 F) and higher, making this an excellent candidate material for ultrahigh temperature applications. To gain increased understanding of the microstructural effects that were resulting in observed mechanical behaviors, a detailed study of W-10vol%Ta and W-10vol%Ta-5vol%TiC alloys including optical and SEM imaging with EDS mapping, TEM imaging, X-ray diffraction, and hardness measurements was performed to examine elemental diffusion and microstructural changes in these two alloys. W-Ta cross diffusion was discovered to occur over a relatively large area on order of 10s of microns, producing a Ta interface region featuring increased hardness than that expected for pure tantalum. Interestingly, interstitial elements such as C and O were found to preferentially migrate to the center of Ta particles, producing regions displaying extremely high hardness in comparison to the surrounding ductile matrices, possibly accounting for the apparent strengthening seen in the W-10vol%Ta samples at both room and elevated temperatures.The loss of strength in W-TiC alloys at 2204 C was disappointing given their excellent grain growth resistance up to 1927 C, therefore work was done investigating the centering and mechanical behavior of W with other nanoparticle additives. This resulted in identification of oxidation of nanoparticle additions in W due to oxygen present in the matrix phase, which is in agreement with previous oxidation seen in W-TiC alloys. A Zener-type model allowed for successful description of grain growth inhibition of W during sintering with carbide particle additions, and a simple model combining the Hall-Petch and second-phase precipitate strengthening mechanisms was capable of prediction alloy hardness values with relative accuracy, alloying for tailoring of W hardness with specific nanoparticle additions to desired values.Tungsten alloys were found to be highly brittle at room temperature regardless of alloying changes, therefore work was also performed exploring room and ultra-high temperature Ta alloys (Chapter 4). This resulted in identification of Ta-10vol%W as an excellent alloy for use over a wide range of temperatures including up to temperatures in excess of 2204 C. It was further demonstrated that this alloy displayed superior mechanical properties to Ta-10vol%W produced by other commercial methods at elevated temperatures which was attributed to the improved microstructure obtained by FAST sintering in comparison to Ta-10vol%W alloys obtained by typical arc casting, forging, and heat treatment methods. Finally, as TiC nanoparticle addition was found to produce extremely strong W alloys up to 1927 C, it was of interest whether use of this alloy was possible with molybdenum, a material used at lower temperatures than tungsten for which the loss of strength seen at 2204 C would not be a concern. Sintering studies were therefore performed determining optimal sintering conditions for production of the molybdenum alloy TZM (titanium zirconium molybdenum) alloys with and without TiC addition (Chapter 5). After determining these conditions, commercial-scale 4x4 plates were sintered at optimized conditions, producing similar densities to that seen in smaller samples demonstrating potential scalability of FAST production of these alloys for commercial-scale sintering. Mechanical testing of these alloys identified the presence of high degrees of ductility in pure TZM samples and TZM-5vol%TiC samples, although this ductility was lost at 10 vol% TiC addition.
Download or read book Modeling and Simulation of Microstructure Evolution in Solidifying Alloys written by Laurentiu Nastac and published by . This book was released on 2004 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Mechanical Properties of Structural Metals and Alloys written by Andrey Belyakov and published by MDPI. This book was released on 2019-06-24 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers collected in this special issue clearly reflect the modern research trends in materials science. These fields of specific attention are high-Mn TWIP steels, high-Cr heat resistant steels, aluminum alloys, ultrafine grained materials including those developed by severe plastic deformation, and high-entropy alloys. The major portion of the collected papers is focused on the mechanisms of microstructure evolution and the mechanical properties of metallic materials subjected to various thermo-mechanical, deformation or heat treatments. Another large portion of the studies is aimed on the elaboration of alloying design of advanced steels and alloys. The changes in phase content, transformation and particle precipitation and their effect on the properties are also broadly presented in this collection, including the microstructure/property changes caused by irradiation.
Download or read book Complex Concentrated Alloys CCAs written by Sundeep Mukherjee and published by MDPI. This book was released on 2020-11-04 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of several unique articles on the current state of research on complex concentrated alloys, as well as their compelling future opportunities in wide ranging applications. Complex concentrated alloys consist of multiple principal elements and represent a new paradigm in structural alloy design. They show a range of exceptional properties that are unachievable in conventional alloys, including high strength–ductility combination, resistance to oxidation, corrosion/wear resistance, and excellent high-temperature properties. The research articles, reviews, and perspectives are intended to provide a wholistic view of this multidisciplinary subject of interest to scientists and engineers.
