Download or read book The Use of Modeling Based Physical Simulation to Reveal the Relationship Between Process Parameters and Microstructural Evolution in Thermal Stir Processed TSP TI6A1 4V written by and published by . This book was released on 2009 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The initial work statement targeted quantifying the hot working conditions experienced by titanium during friction stir welding/processing (FSW/P). Of particular interest was the identification of the hot working conditions (i.e. strain rate, strain, and temperature) required to refine the grains in the weld zone or nugget. Using a kinematic approach toward modeling of the FSW/P, the instantaneous shear strain rate encountered by the material entering the rotation plug around the weld tool is estimated to be in the range of 103 to 106 s-l at strains levels in excess of 50. A similar level of grain refinement has been reported in metal chips formed during cutting operations where the shear strain rate is estimated to be in the range of 103 to 106 s-l, but at strain levels less than 5. Both these processes are predicted to instantaneously impart strain rates on the order of ballistic impact on the metal. In contrast grain refinement has also been reported in equal channel angular extrusion (ECAE) where the grain size reduction has been correlated with the increasing amount of strain achieved by multi passes at quasi-static strain rates. The motivation for this study is furthering our understanding of the mechanics responsible for grain refinement as influenced by ballistic level sheer strain rate and/or shear strain.

Download or read book The Microstructural Evolution and Constitutive Analysis for a Physical Simulation of Friction Stir Processing of Ti 6Al 4V written by Jason James Livingston and published by . This book was released on 2011 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Friction stir processing above the [beta]-transus was microstructurally evident by a stir zone composed of 10 - 40um recrystallized [beta]-grains with either a basketweave or lamellar structure and a continuous network of [alpha] at the grain boundary. Moreover, processing below the [beta]-transus provided a dimensionless heat input of Q = 37.5, while processing above the [beta]-transus was Q less than 50, suggesting this dimensionless heat input does not correlate well with the resulting microstructures.

Download or read book Modeling and Simulation of Microstructure Evolution in Solidifying Alloys written by Laurentiu Nastac and published by Springer Science & Business Media. This book was released on 2004-05-31 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of Modeling and Simulation of Microstructure Evolution in Solidifying Alloys is to describe in a clear mathematical language the physics of the solidification structure evolution of cast alloys. The concepts and methodologies presented here for the net-shaped casting and the ingot remelt processes can be applied, with some modifications, to model other solidification processes such as welding and deposition processes. Another aim of the book is to provide simulation examples of the solidification structure modeling in some crucial commercial casting technologies as well as to provide practical techniques for controlling the structure formation during the solidification processes.

Download or read book Modeling Characterizing and Reconstructing Mesoscale Microstructural Evolution in Particulate Processing and Solid state Sintering written by Shaohua Chen and published by . This book was released on 2018 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: In material science, microstructure plays a key role in determining properties, which further determine utility of the material. However, effectively measuring microstructure evolution in real time remains an challenge. To date, a wide range of advanced experimental techniques have been developed and applied to characterize material microstructure and structural evolution on different length and time scales. Most of these methods can only resolve 2D structural features within a narrow range of length scale and for a single or a series of snapshots. The currently available 3D microstructure characterization techniques are usually destructive and require slicing and polishing the samples each time a picture is taken. Simulation methods, on the other hand, are cheap, sample-free and versatile without the special necessity of taking care of the physical limitations, such as extreme temperature or pressure, which are prominent issues for experimental methods. Yet the majority of simulation methods are limited to specific circumstances, for example, first principle computation can only handle several thousands of atoms, molecular dynamics can only efficiently simulate a few seconds of evolution of a system with several millions particles, and finite element method can only be used in continuous medium, etc. Such limitations make these individual methods far from satisfaction to simulate macroscopic processes that a material sample undergoes up to experimental level accuracy. Therefore, it is highly desirable to develop a framework that integrate different simulation schemes from various scales to model complicated microstructure evolution and corresponding properties. Guided by such an objective, we have made our efforts towards incorporating a collection of simulation methods, including finite element method (FEM), cellular automata (CA), kinetic Monte Carlo (kMC), stochastic reconstruction method, Discrete Element Method (DEM), etc, to generate an integrated computational material engineering platform (ICMEP), which could enable us to effectively model microstructure evolution and use the simulated microstructure to do subsequent performance analysis. In this thesis, we will introduce some cases of building coupled modeling schemes and present the preliminary results in solid-state sintering. For example, we use coupled DEM and kinetic Monte Carlo method to simulate solid state sintering, and use coupled FEM and cellular automata method to model microstrucutre evolution during selective laser sintering of titanium alloy. Current results indicate that joining models from different length and time scales is fruitful in terms of understanding and describing microstructure evolution of a macroscopic physical process from various perspectives.

Download or read book Modelling the Deformation Recrystallization and Microstructure Related Properties in Metals written by Jurij J Sidor and published by Mdpi AG. This book was released on 2021-11-15 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the special issue related to Modelling the Deformation, Recrystallization and Microstructure-Related Properties in Metals, we presented a wide spectrum of articles dealing with modelling of microstructural aspects involved in deformation and recrystallization as well as simulation of microstructure-based and texture-based properties in various metals. The latest advances in the theoretical interpretation of mesoscopic transformations based on experimental observations were partially discussed in the current special issue. The studies dealing with the modelling of structure-property relationships are likewise analyzed in the present collection of manuscripts. The contributions in the current collection evidently demonstrate that the properties of metallic materials are microstructure dependent and therefore the thermomechanical processing (TMP) of the polycrystalline aggregates should be strictly controlled to guarantee the desired bunch of qualities. Given this, the assessment of microstructure evolution in metallic systems is of extraordinary importance. Since the trial-error approach is a time-consuming and quite expensive methodology, the materials research community tends to employ a wide spectrum of computational approaches to simulate each chain of TMP and tune the processing variables to ensure the necessary microstructural state which will provide desired performance in the final product. Although many hidden facets of various technological processes and related microstructural changes were revealed in the submitted works by employing advanced computational approaches, nevertheless, the contributions collected in this issue clearly show that further efforts are required in the field of modelling to understand the complexity of material's world. The final goal of modelling efforts might be a development of a comprehensive model, which will be capable of describing many aspects of microstructure evolution during thermomechanical processing.

Download or read book Modeling of Thermal and Mechanical Effects During Friction Stir Processing of Nickel Aluminum Bronze written by Jay D. Jamison and published by . This book was released on 2004-09-01 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Friction Stir Processing (FSP), although relatively simple in concept, results in an extremely complex thermomechanical treatment to the material being processed. Previous studies of FSP have shown that the process results in extremely high strain, strain rates and temperatures as well as gradients in strain, strain rate and temperature within a small volume of material. This thesis will study the effect of varying FSP parameters during the processing of Nickel-Aluminum- Bronze (NAB) propeller material. The modeling program CTH was used to define the relationship between tool rotation speed, traversing speed and the total power input to the material. The tool s mechanical power and the power generated by deformation of the material has been investigated. The modeling experiments were designed to gain an understanding of the relationship of process parameters, microstructure and mechanical properties, and to enhance our understanding of the flow patterns and thermal histories of the NAB material in the stir zone.

Download or read book Microstructural Evolution of Friction Stir Processed Ti 6Al 4V written by Paul Andrew Pavka and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Friction stir welding has been developed over the past ten years to permit joining of high strength alloys that cannot be fusion welded. More recently friction stir processing (FSP) has been shown to alter the surface microstructure of a material by essentially in situ thermo mechanical processing. In this study we have used FSP to alter the surface microstructure of Ti-6Al-4V. In all trials, the friction stir processing (FSP) applied to the surface of cast +H.I.P. slabs has resulted in changing the coarse lamellae to small equiaxed [alpha] grains that are about 1 in diameter. This process leaves the coarse lamellar microstructure in the bulk of the material. These findings are believed to produce a microstructure that will have better fatigue strength than what was previously available from the cast + H.I.P. coarse microstructure. Orientation imaging microscopy (OIM) of the fine-grained, equiaxed process zone has shown that there is no preferred grain orientation. A new technique for locally measuring yield strength using small, in-situ compressive cylinders (pillars) has been used to determine the strength change between the fine grain and as-cast structure. Pillars made from focused ion beam milling (FIB) have demonstrated that the fine-grained stirred material is about 30% stronger than the as-cast material. Definition of the mechanism that controls the conversion from the lamellar structure to the equiaxed structure is still being developed, but several observations suggest that the -transus has not been exceeded. More work is being done to verify the fatigue strength of the new microstructure, and to develop a better understanding of the mechanism that controls the conversion process. This work is ongoing but the microstructure changes associated with FSP are described in here.

Download or read book Dependence of Microstructure Evolution Texture and Mechanical Behavior of a Magnesium Alloy on Thermo mechanical Input During Friction Stir Processing written by Zhenzhen Yu and published by . This book was released on 2010 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the relationship among friction stir processing (FSP) parameters, microstructure evolution, texture development, and mechanical hehavior[sic] of AZ31B Mg alloy was investigated. First of all, in order to reveal the correlation among the deformation conditions, dynamic recrystallization (DRX) mechanisms, and microstructure evolution in the Mg alloy, hot compression tests at a wide range of Zener-Hollomon parameter (Z) values were conducted. Through optical microscopic examination, it was found out that above a critical Z value, twinning influences the DRX process resulting in a more effective grain refinement, which is manifested in a significant change in the slope of the Z-d[subscript rec] relationship, where d[subscript rec] is the recrystallized grain size. Moreover, EBSD examination revealed that the twinning also contributed to a distinct change in the recrystallization texture. Compression tests were performed along both through-thickness and in-rolling-plane directions of the plate to study the orientation dependency of twinning activities and its influence on the DRX process. X-ray line profile analysis (XLPA) provides further insights by highlighting the differences in the dislocation density/types, subgrain sizes, and twin densities during the DRX processes operating with or without the twinning. Secondly, the constitutive behaviour study was applied to the investigation of microstructure evolution during FSP. By varying the key FSP parameters systematically, i.e. rotation and travel rates of the tool, a series of FSP specimens were prepared with a wide range of thermo-mechanical inputs in terms of Z. The resulting tensile behavior in the stir zone (SZ) showed a dramatic change as a function of Z, caused by a systematic change in the texture within SZ measured by neutron diffraction. A three-dimensional transient model was developed to investigate the detailed deformation history including the temperature and strain rate profiles and material flow pattern during FSP of the Mg alloy. Such deformation history can be combined with the constitutive study from the compression tests in order to analyze the developments of micro-texture and DRX grains during FSP, which will, in turn, dominate the mechanical properties. Based on the studies above, new fundamental understandings were gained on the governing mechanisms for the deformation and recrystallization processes during FSP and the influence of thermo-mechanical input during FSP on ductility enhancement in the Mg alloy.

Download or read book Phase Field Modeling of Microstructure Evolution in Thermal Barrier Coating Systems written by Karim E. Ahmed and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The development of robust thermal barrier coating (TBC) systems is crucial in many high-temperature applications. The performance of a TBC system is significantly limited by microstructural evolution mechanisms, such as sintering at elevated temperatures. Sintering reduces the porosity of TBC and makes it denser which eventually increases the thermal conductivity and reduces the strain compliance of TBC. Understanding how sintering proceeds in TBC systems is thus important in improving the design of such systems. An elaborate phase field model was developed in order to understand the sintering behavior of columnar TBC structure. The model takes into account different sintering mechanisms, such as volume diffusion, grain boundary diffusion, surface diffusion, and grain boundary migration, coupled with elastic strain arising from the thermal expansion mismatch in thermal barrier coating system. Direct relations between model parameters and material properties were established. Such relations facilitate quantitative studies of the sintering process in any material of interest. The model successfully demonstrates a strong dependence of the sintering process in TBC on the initial morphology and dimensions of coatings, strain, and temperature.

Download or read book Introduction to Surface and Thin Film Processes written by John Venables and published by Cambridge University Press. This book was released on 2000-08-31 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the experimental and theoretical understanding of surface and thin film processes. It presents a unique description of surface processes in adsorption and crystal growth, including bonding in metals and semiconductors. Emphasis is placed on the strong link between science and technology in the description of, and research for, new devices based on thin film and surface science. Practical experimental design, sample preparation and analytical techniques are covered, including detailed discussions of Auger electron spectroscopy and microscopy. Thermodynamic and kinetic models of structure are emphasised throughout. The book provides extensive leads into practical and research literature, as well as resources on the World Wide Web (see http://venables.asu.edu/book). Each chapter contains problems which aim to develop awareness of the subject and the methods used. Aimed as a graduate textbook, this book will also be useful as a sourcebook for graduate students, researchers and practitioners in physics, chemistry, materials science and engineering.

Download or read book Ceramic Microstructures written by Antoni P. Tomsia and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume, titled Proceedings of the International Materials Symposium on Ce ramic Microstructures: Control at the Atomic Level summarizes the progress that has been achieved during the past decade in understanding and controlling microstructures in ceram ics. A particular emphasis of the symposium, and therefore of this volume, is advances in the characterization, understanding, and control of micro structures at the atomic or near-atomic level. This symposium is the fourth in a series of meetings, held every ten years, devoted to ceramic microstructures. The inaugural meeting took place in 1966, and focussed on the analysis, significance, and production of microstructure; the symposium emphasized the need for, and importance of characterization in achieving a more complete understanding of the physical and chemical characteristics of ceramics. A consensus emerged at that meeting on the critical importance of characterization in achieving a more complete understanding of ceramic properties. That point of view became widely accepted in the ensuing decade. The second meeting took place in 1976 at a time of world-wide energy shortages and thus emphasized energy-related applications of ceramics, and more specifically, microstructure-property relationships of those materials. The third meeting, held in 1986, was devoted to the role that interfaces played both during processing, and in influencing the ultimate properties of single and polyphase ceramics, and ceramic-metal systems.

Download or read book Titanium Alloys written by Maciej Motyka and published by BoD – Books on Demand. This book was released on 2019-11-27 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanium alloys, due to unique physical and chemical properties (mainly high relative strength combined with very good corrosion resistance), are considered as an important structural metallic material used in hi-tech industries (e.g. aerospace, space technology). This book provides information on new manufacturing and processing methods of single- and two-phase titanium alloys. The eight chapters of this book are distributed over four sections. The first section (Introduction) indicates the main factors determining application areas of titanium and its alloys. The second section (Manufacturing, two chapters) concerns modern production methods for titanium and its alloys. The third section (Thermomechanical and surface treatment, three chapters) covers problems of thermomechanical processing and surface treatment used for single- and two-phase titanium alloys. The fourth section (Machining, two chapters) describes the recent results of high speed machining of Ti-6Al-4V alloy and the possibility of application of sustainable machining for titanium alloys.

Download or read book Marine Corrosion written by and published by . This book was released on 1977 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Matrix Composites written by Nikhilesh Chawla and published by Springer Science & Business Media. This book was released on 2006-01-16 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few years, a significant increase in applications of MMCs has taken place, particularly in the areas of automotive, aerospace, electronics, and recreation. These include continuous fiber reinforced MMCs for cables in power transmission, high temperature superconducting wires, particulate MMCs in civilian aircraft and automotive applications, and high volume fraction, high thermal conductivity substrates for electronic packaging. Nevertheless, as with any novel material systems, there is a lack of fundamental understanding on the part of practicing engineers and designers. This book would seek to address these issues, in a thorough and cohesive manner, as well as to provide students and scientists with a basic understanding of MMCs. This book will emphasize the synergistic relationships among processing, structure, and properties of metal matrix composites.

Download or read book Physics at Surfaces written by Andrew Zangwill and published by Cambridge University Press. This book was released on 1988-03-24 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics at Surfaces is a unique graduate-level introduction to the physics and chemical physics of solid surfaces, and atoms and molecules that interact with solid surfaces. A subject of keen scientific inquiry since the last century, surface physics emerged as an independent discipline only in the late 1960s as a result of the development of ultra-high vacuum technology and high speed digital computers. With these tools, reliable experimental measurements and theoretical calculations could at last be compared. Progress in the last decade has been truly striking. This volume provides a synthesis of the entire field of surface physics from the perspective of a modern condensed matter physicist with a healthy interest in chemical physics. The exposition intertwines experiment and theory whenever possible, although there is little detailed discussion of technique. This much-needed text will be invaluable to graduate students and researchers in condensed matter physics, physical chemistry and materials science working in, or taking graduate courses in, surface science.

Download or read book Introduction to Surface Physics written by M. Prutton and published by . This book was released on 1994 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Uhlig s Corrosion Handbook written by Robert Winston Revie and published by . This book was released on 2011 with total page 1253 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book serves as a reference for engineers, scientists, and students concerned with the use of materials in applications where reliability and resistance to corrosion are important. It updates the coverage of its predecessor, including coverage of: corrosion rates of steel in major river systems and atmospheric corrosion rates, the corrosion behavior of materials such as weathering steels and newer stainless alloys, and the corrosion behavior and engineering approaches to corrosion control for nonmetallic materials. New chapters include: high-temperature oxidation of metals and alloys, nanom.