Download or read book Fundamental Investigations of Creep and Fatigue of Dispersion Strengthened Nb Alloys written by and published by . This book was released on 1995 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the three years of this program, the creep studies focused on a select precipitation strengthened alloy of niobium shown to possess superior creep resistance at stress levels normally targeted in design applications. The alloy selected was a carbide precipitation strengthened niobium-zirconium-alloy (Nb-1wt%Zr-0.1wt%C) commercially known as PWC-11. The carbide precipitations are produced in-situ during the thermomechanical processing of the material and have proven to be extremely stable at service temperature. Transmission electron microscopy was used to examine both the internal structure of the crept material as well as the size distribution of the carbide particles extracted from the metal matrix. X-ray diffraction analysis of the extracted carbide particles identified their chemical make-up necessary for characterizing their thermodynamic stability. A thermodynamic model was developed which supports the observed parameters of the carbide precipitates and thus is useful in predicting the high temperature mechanical properties of this and similar alloy systems. jg p1.

Download or read book Strengthening Mechanisms Creep and Fatigue Processes in Dispersion Hardened Niobium Alloy written by and published by . This book was released on 1992 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The creep and fatigue properties of pure Nb and Nb-l%Zr alloy were investigated. A model was developed based on the migration of subgrain boundary that can explain the anomalous primary creep transients found in Nb-l%Zr alloy, due to coarsening of subgrain structure. TEM investigations confirmed that such subgrain coarsening occurs during primary creep of Nb-l%Zr. Baseline low cycle fatigue studies of Nb and Nb-l%Zr were completed. Cyclic hardening is observed and there is a microplastic plateau in Nb. The Nb-1%Zr is stronger in cyclic deformation than Nb, with little influence of strain rate. The deformation in the alloy at both high and low strain rates is controlled by the interaction between gliding edge dislocation and solute atoms. Creep, fatigue, niobium alloy, dislocation mechanisms.

Download or read book Fundamental Investigations of High temperature Creep of a Particle strengthened Niobium Alloy written by David Michael Farkas and published by . This book was released on 1995 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Strain of Metals and Alloys written by Valim Levitin and published by John Wiley & Sons. This book was released on 2006-05-12 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Creep and fatigue are the most prevalent causes of rupture in superalloys, which are important materials for industrial usage, e.g. in engines and turbine blades in aerospace or in energy producing industries. As temperature increases, atom mobility becomes appreciable, affecting a number of metal and alloy properties. It is thus vital to find new characterization methods that allow an understanding of the fundamental physics of creep in these materials as well as in pure metals. Here, the author shows how new in situ X-ray investigations and transmission electron microscope studies lead to novel explanations of high-temperature deformation and creep in pure metals, solid solutions and superalloys. This unique approach is the first to find unequivocal and quantitative expressions for the macroscopic deformation rate by means of three groups of parameters: substructural characteristics, physical material constants and external conditions. Creep strength of the studied up-to-date single crystal superalloys is greatly increased over conventional polycrystalline superalloys. From the contents: - Macroscopic characteristics of strain at high temperatures - Experimental equipment and technique of in situ X-ray investigations - Experimental data and structural parameters in deformed metals - Subboundaries as dislocation sources and obstacles - The physical mechanism of creep and the quantitative structural model - Simulation of the parameters evolution - System of differential equations - High-temperature deformation of industrial superalloys - Single crystals of superalloys - Effect of composition, orientation and temperature on properties - Creep of some refractory metals For materials scientists, solid state physicists, solid state chemists, researchers and practitioners from industry sectors including metallurgical, mechanical, chemical and structural engineers.

Download or read book A Survey of Dispersion Strengthening of Metals and Alloys summary Technical Report written by Rointan Framroze Bunshah and published by . This book was released on 1959 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamentals of Creep in Metals and Alloys written by Michael E. Kassner and published by Elsevier. This book was released on 2004-04-06 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: * Numerous line drawings with consistent format and units allow easy comparison of the behavior of a very wide range of materials * Transmission electron micrographs provide a direct insight in the basic microstructure of metals deforming at high temperatures * Extensive literature review of over 1000 references provide an excellent reference document, and a very balanced discussionUnderstanding the strength of materials at a range of temperatures is critically important to a huge number of researchers and practitioners from a wide range of fields and industry sectors including metallurgists, industrial designers, aerospace R&D personnel, and structural engineers. The most up-to date and comprehensive book in the field, Fundamentals of Creep in Metals and Alloys discusses the fundamentals of time-dependent plasticity or creep plasticity in metals, alloys and metallic compounds. This is the first book of its kind that provides broad coverage of a range of materials not just a sub-group such as metallic compounds, superalloys or crystals. As such it presents the most balanced view of creep for all materials scientists. The theory of all of these phenomena are extensively reviewed and analysed in view of an extensive bibliography that includes the most recent publications in the field. All sections of the book have undergone extensive peer review and therefore the reader can be sure they have access to the most up-to-date research, fully interrogated, from the world's leading investigators.· Numerous line drawings with consistent format and units allow easy comparison of the behavior of a very wide range of materials· Transmission electron micrographs provide a direct insight in the basic microstructure of metals deforming at high temperatures· Extensive literature review of over 1000 references provide an excellent reference document, and a very balanced discussion

Download or read book Creep and Tensile Properties of Several Oxide dispersion strengthened Nickel base Alloys at 1365 K written by John Daniel Whittenberger and published by . This book was released on 1977 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diffusional Creep and Creep Degradation in the Dispersion strengthened Alloy TD NiCr written by John Daniel Whittenberger and published by . This book was released on 1972 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dispersoid-free regions were observed in TD-NiCr (Ni-20Cr-2ThO2) after slow strain rate testing in air from 1145 to 1590 K. Formation of the dispersoid-free regions appears to be the result of diffusional creep. The net effect of this creep is the degradation of TD-NiCr to a duplex microstructure. Degradation is further enhanced by the formation of voids and integranular oxidation in the thoria-free regions. These regions apparently provided sites for void formation and oxide growth since the strength and oxidation resistance of Ni-20Cr is much less than Ni-20Cr-2ThO2. This localized oxidation does not appear to reduce the static load bearing capacity of TD-NiCr since long stress rupture lives were observed even with heavily oxidized microstructures. But this oxidation does significantly reduce the ductility and impact resistance of the material. Dispersoid-free bands and voids were also observed for two other dispersion strengthened alloys, TD-NiCrAl and IN-853. Thus, it appears that diffusional creep is charactertistic of dispersion-strengthened alloys and can play a major role in the creep degradation of these materials.

Download or read book Investigation of the Strengthening Mechanisms of Dispersion strengthened Alloys written by Richard J. Murphy and published by . This book was released on 1964 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to produce dispersion-strengthened alloys with more versatile strength properties than those reported for oxide dispersion strengthened systems, the systems Ni-TiC and Ni-TiB2 were studied. Diffusion couples of dilute alloys of Ni-C and Ni-Ti as well as of Ni-B and Ni-Ti were studied to determine the conditions necessary for the formation of a fine dispersion of TiC and TiB2 in nickel. TiB2 was found to be unsuitable for this type of application. Nickel-base alloys with a dispersion of TiC were prepared by several powder metallurgical techniques as well as by internal carburization of Ni-Ti chips. The mechanical properties of these alloys were studied at room temperature and 815C and a comparison made with the properties of conventional alloys reported for these temperatures. Transmission electron microscopy was used to study the elastic strain fields associated with dispersoid particles in the Ni-Al2O3 and Cu-Al2O3 systems, prepared by internal oxidation. (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 An Investigation of the Structure and High Temperature Mechanical Properties of Oxide Dispersion Strengthened Alloys written by William D. Nix and published by . This book was released on 1982 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure and high temperature mechanical properties of oxide dispersion strengthened alloys are being studied. We have observed and studied superplastic properties in fine grained MA 6000 and MA 754. These properties have been described by model which couples dislocation and diffusional creep. The creep properties of coarse grained MA 754 are also being studied. We have observed that cavitation contributes to the creep rate at low stresses and high temperatures and that grain boundary degradation occurs by diffusional processes. Work on the structure and properties of A1-Fe-Ce alloys is just starting.

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 1146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Creep and Tensile Properties of Several Oxide Dispersion Strengthened Nickel Base Alloys at 1365 K written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-06 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tensile properties at room temperature and at 1365 K and the tensile creep properties at low strain rates at 1365 K were measured for several oxide-dispersion-strengthened (ODS) alloys. The alloys examined included ODS Ni, ODS Ni-20Cr, and ODS Ni-16Cr-Al. Metallography of creep tested, large grain size ODS alloys indicated that creep of these alloys is an inhomogeneous process. All alloys appear to possess a threshold stress for creep. This threshold stress is believed to be associated with diffusional creep in the large grain size ODS alloys and normal dislocation motion in perfect single crystal (without transverse low angle boundaries) ODS alloys. Threshold stresses for large grain size ODS Ni-20Cr and Ni-16Cr-Al type alloys are dependent on the grain aspect ratio. Because of the deleterious effect of prior creep on room temperature mechanical properties of large grain size ODS alloys, it is speculated that the threshold stress may be the design limiting creep strength property. Wittenberger, J. D. Glenn Research Center NASA-TN-D-8422, E-8882 RTOP 505-01

Download or read book Creep Strength of Niobium Alloys Nb 1 zr and Pwc 11 written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-12-29 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study is being conducted at NASA Lewis Research Center to determine the feasibility of using a carbide particle strengthened Nb-1 percent Zr base alloy to meet the anticipated temperature and creep resistance requirements of proposed near term space power systems. In order to provide information to aid in the determination of the suitability of the PWC-11 alloy as an alternative to Nb-1 percent Zr in space power systems this study investigated: (1) the long-time high-vacuum creep behavior of the PWC-11 material and the Nb-1 percent Zr alloy, (2) the effect of prior stress-free thermal aging on this creep behavior, (3) the effect of electron beam (EB) welding on this creep behavior, and (4) the stability of creep strengthening carbide particles. Titran, Robert H. Glenn Research Center NASA-TM-102390, E-5102, DOE/NASA/16310-13, NAS 1.15:102390 DE-AI03-86SF-16310; RTOP 586-01-11...

Download or read book Analysis and Modelling of the Creep fatigue Behaviour of Oxide Dispersion Strengthened Superalloys written by D. M. Elzey and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Creep and Tensile Properties of Several Oxide dispersion strengthened Nickel base Alloys at 1365 K written by J. Daniel Whittenberger and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Creep of Dispersion Strengthened Ni Co Alloys written by J. HANCOCK and published by . This book was released on with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: