Download or read book The Mechanical Properties and Oxidation Behavior of Nanocrystalline NiAl Synthesized Via Shock Consolidation of Mechanically Alloyed Powders of Ni and Al written by Tao Chen and published by . This book was released on 1999 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1999-04 with total page 972 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2000 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts Index written by and published by . This book was released on 1996 with total page 1622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study on Formation and Thermal Stability of Nano sized Oxide Clusters in Mechanically Alloyed NiAl for High Temperature Applications written by YONG-DEOG. KIM and published by . This book was released on 2012 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The intermetallic compound, B2 NiAl, is a promising material for high temperature structural applications such as in aviation jet engines or gas turbines, provided that its high temperature mechanical properties can be improved. Although extensive efforts over the last several decades have been devoted toward enhancing ductility through alloying design and reducing impurities, as well as improving high temperature creep strength through precipitation and dispersion strengthening, these efforts have relied on traditional approaches, a combination of large grain size to limit diffusional creep and precipitation/dispersion (50 ~ 100 nm size) strengthening to limit dislocation creep, for high temperature strengthening. While traditional approaches have shown a good improvement from a relatively high temperature strengthening point of view, the size and number density of dispersoids were not able to provide sufficient strength in the high temperature creep regime. Furthermore, details of the interaction mechanism between dislocations and dispersoids are not yet well understood. This study focuses on designing and developing advanced oxide dispersion strengthened (ODS) NiAl intermetallics with improved high temperature creep strength by incorporating a high number density (~1024 m-3) of very thermally stable Y-Ti-O nano-clusters, akin to those recently observed to improve creep strength and radiation resistance in nano-structured ferritic alloys. Advanced ODS NiAl alloys have been produced by mechanical alloying of pre-alloyed Ni-50at%Al with Y2O3 and Ti elemental powders. The milled powders were subsequently consolidated by spark plasma sintering, with the objective of producing very high number densities of nano-sized Y-Ti-O precipitates, along with fine grain size. Advanced experimental characterization techniques, combined with microhardness strength measurement, were used to investigate the material microstructure and strength following processing and to evaluate the thermal stability during an extensive matrix of long-term thermal annealing. In particular, the size, number density and composition of nano-clusters were assessed. While improvements in strength were obtained in the advanced NiAl ODS alloys, and the higher strength persisted through thermal annealing for 100 hrs at 1723K, characterization revealed the presence of Al in the oxide precipitate phases. The Al incorporation is believed detrimental to the formation of a high density of thermally stable Y-Ti-O nanoscale precipitates.
Download or read book Nanocrystalline Alloys written by Timothy John Rupert and published by . This book was released on 2011 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline materials have experienced a great deal of attention in recent years, largely due to their impressive array of physical properties. In particular, nanocrystalline mechanical behavior has been of interest, as incredible strengths are predicted when grain size is reduced to the nanometer range. The vast majority of research to this point has focused on quantifying and understanding the grain size-dependence of strength, leading to the discovery of novel, grain boundary-dominated physics that begin to control deformation at extremely fine grain sizes. With the emergence of this detailed understanding of nanocrystalline deformation mechanisms, the opportunity now exists for studies that explore how other structural features affect mechanical properties in order to identify alternative strengthening mechanisms. In this thesis, we seek to extend our current knowledge of nanocrystalline structure-property relationships beyond just grain size, using combinations of structural characterization, mechanical testing, and atomistic simulations. Controlled experiments on Ni-W are first used to show that solid solution addition and the relaxation of nonequilibrium grain boundary state can dramatically affect the strength of nanocrystalline metals. Next, the sliding wear response of nanocrystalline Ni-W is investigated, to show how alloying and grain boundary structural state affect a more complex mechanical property. This type of mechanical loading also provides a strong driving force for structural evolution, which, in this case, is found to be beneficial. Mechanically-driven grain growth and grain boundary relaxation occur near the surface of the Ni-W samples during sliding, leading to a hardening effect that improves wear resistance and results in a deviation from Archard scaling. Finally, molecular dynamics simulations are performed to confirm that mechanical cycling alone can indeed relax grain boundary structure and strengthen nanocrystalline materials. In all of the cases discuss above, our observations can be directly connected to the unique deformation physics of nanocrystalline materials.
Download or read book Mechanical Properties of Nanocrystalline Metals Intermetalics and Multiphase Materials Determined by Tension Compression and Disk bend Techniques written by and published by . This book was released on 1997 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanical behavior of nanocrystalline metallic, intermetallic, and multiphase materials was investigated using tension, compression, and disk-bend techniques. Nanocrystalline NiAl, Al-Al3Zr, and Cu were synthesized by gas condensation and either resistive or electron beam heating followed by high temperature vacuum compaction. Disk- bend tests of nanocrystalline NiAl show evidence of improved ductility at room temperature in this normally extremely brittle material. In contrast, tension tests of multiphase nanocrystalline Al- Al3Zr samples show significant increases in strength by substantial reductions in ductility with decreasing grain size. Compression tests of nanocrystalline copper result in substantially higher yield stress and total elongation values than those measured in tensile tests. Implications for operative deformation mechanisms in these materials are discussed.
Download or read book On the Mechanical Behavior of Nanocrystalline Ni Based Alloys written by Thomas Robert Koenig and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fabrication and characterization of a ternary nanocrystalline (NC) stabilized Ni-Cu-P alloy was reported. The complexities of fabrication a low contamination, equiaxed NC material was discussed. For comparison, elemental Ni was prepared via sputter deposition, highlighting the difficulty in fabricating an idealized structure within the confines of the parametric space. An exchange between the ideal grain size distribution and film coalescence was discussed with the ramifications of substrate heat, deposition pressure, and deposition rate considered. These results were then compared to a kinetic model to assess the validity of the model and its ability to capture the complex growth behavior noted between the Ni films.A series of ternary NC Ni-Cu-P thin films were fabricated, characterized, and loaded via in situ annealing and nanoindentation. Examination of the thermal stability behavior revealed differences in precipitation behavior as a function of Cu and P solute content. Furthermore the Ni-40Cu-0.6P (at.%) alloy was noted as the only NC stabilized composition at 550 ©2℗ʻC. The Ni-40Cu-0.3P deposit developed nanoscale precipitates upon annealing to temperatures of 550 ©2℗ʻC which ultimately resided in the matrix. It was found that the ternary Ni-Cu-P films are harder than previously studied binary Ni-1P and Ni-4P (at.%) systems. Adding Cu to the Ni-P system promoted solid solution strengthening which mitigated softening in those binary alloys previously reported.A MEMS device was then employed for in situ thermomechanical testing of the stabilized Ni-40Cu-0.6P film for comparison with a binary Ni-40Cu counterpart. Digital image correlation (DIC) was employed to data mine microstructural evolutions that occurred while the films were loaded. Increased fracture strength was reported with the P solute addition, irrespective of the loading temperature. The ramifications of adding this stabilizing solute were discussed with respect to the fracture profile and microstructural stability.
Download or read book Investigation of the Oxidation Behavior of High Strength NiAl Alloys written by Arthur Lee Brown and published by . This book was released on 2008 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Chemical Composition on Mechanical Properties of Mechanically Alloyed NiAl based Alloys written by Chu-Chun Chao and published by . This book was released on 1994 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Composites Industry Abstracts written by and published by . This book was released on 1996 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Alloying And Milling written by Cury Suryanarayana and published by CRC Press. This book was released on 2004-09-28 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book surveys the broad field of mechanical alloying from a scientific and technological perspective to form a timely and comprehensive resource valuable to both students and researchers. The treatment progresses from the historical background through a description of the process, the different metastable effects produced, and the mechanisms of
Download or read book Nanocrystalline and Bimodal Fe Cr Alloys written by Mahesh Brahmadesham Venkataraman and published by . This book was released on 2013 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystalline (nc) materials, a single or multi-phase polycrystalline solids with a grain size of
Download or read book Carbon Nanotubes written by Andy Nieto and published by CRC Press. This book was released on 2021-05-18 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: This discovery of carbon nanotubes (CNT) three decades ago ushered in the technological era of nanotechnology. Among the most widely studied areas of CNT research is their use as structural reinforcements in composites. This book describes the development of CNT reinforced metal matrix composites (CNT-MMCs) over the last two decades. The field of CNT-MMCs is abundant in fundamental science, rich in engineering challenges and innovations and ripe for technological maturation and commercialization. The authors have sought to present the current state of the-art in CNT-MMC technology from their synthesis to their myriad potential end-use applications. Specifically, topics explored include: • Advantages, limitations, and evolution of processing techniques used to synthesize and fabricate CNT-MMCs • Emphasizes dispersion techniques of CNTs in metallic systems, a key challenge to the successful and widespread implementation of CNT-MMCs. Methods for quantification and improved control of CNT distributions are presented • Methods for quantification and improved control of CNT distributions are presented • Characterization techniques uniquely suited for charactering these nanoscale materials and their many chemical and physical interactions with the metal matrix, including real-time in-situ characterization of deformation mechanisms • Electron microscope images from premier studies enrich discussions on micro-mechanical modeling, interfacial design, mechanical behavior, and functional properties • A chapter is dedicated to the emergence of dual reinforcement composites that seek to enhance the efficacy of CNTs and lead to material properties by design This book highlights seminal findings in CNT-MMC research and includes several tables listing processing methods, associated CNT states, and resulting properties in order to aid the next generation of researchers in advancing the science and engineering of CNT-MMCs. In addition, a survey of the patent literature is presented in order to shed light on what the first wave of CNT-MMC commercialization may look like and the challenges that will have to be overcome, both technologically and commercially.
Download or read book Manufacturing and Application of Stainless Steels written by Andrea Di Schino and published by MDPI. This book was released on 2020-04-15 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stainless steels represent a quite interesting material family, both from a scientific and commercial point of view, following to their excellent combination in terms of strength and ductility together with corrosion resistance. Thanks to such properties, stainless steels have been indispensable for the technological progress during the last century and their annual consumption increased faster than other materials. They find application in all these fields requiring good corrosion resistance together with ability to be worked into complex geometries. Despite to their diffusion as a consolidated materials, many research fields are active regarding the possibility to increase stainless steels mechanical properties and corrosion resistance by grain refinement or by alloying by interstitial elements. At the same time innovations are coming from the manufacturing process of such a family of materials, also including the possibility to manufacture them starting from metals powder for 3D printing. The Special Issue scope embraces interdisciplinary work covering physical metallurgy and processes, reporting about experimental and theoretical progress concerning microstructural evolution during processing, microstructure-properties relations, applications including automotive, energy and structural.
