Download or read book Dislocation Substructure Formed During Creep in Molybdenum Single Crystals written by Allan H. Clauer and published by . This book was released on 1968 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dislocation Substructure Induced by Creep in Molybdenum Single Crystals written by A. H. CLAUER and published by . This book was released on 1970 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dislocation Substructures in Cyclically Deformed Molybdenum Single Crystals written by Jose Antonio Planell-Estany and published by . This book was released on 1983 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-06 with total page 1216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dislocations and Mechanical Properties of Single Crystal Molybdenum Silicide written by Stuart Andrew Maloy and published by . This book was released on 1994 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dislocations and mechanical properties of single crystal MoSi2 have been investigated. Specimens were tested in compression along (001), (021), and (771) axes at strain rates of 1 × 10̄−4/s and 1 × 10−5/s and at temperatures ranging from 900-1600°C in vacuum or argon. The yield stress along (001) was an order of magnitude greater than that measured along (021) or (771) and along all orientations the yield stress was strongly dependent on temperature. Rate jump tests performed along (001) at 1400°C revealed that the yield stress was rate sensitive with a stress exponent of 4. The activated slip systems were determined using optical slip trace analyses and techniques in transmission electron microscopy. Slip occurred via five different slip systems (11100, 13100, 1001/2111, 131/2331, and 111/2111) depending on the orientation, temperature and strain rate at which each test was performed. The critical resolved shear stress was determined for the activated slip systems from the measured 0.2% yield stresses. At 900-1100°C, the lo west critical resolved shear stresses were for slip on the 11100, 1101/2111 and 131/2331 slip systems while at 1200-1600°C the lowest critical resolved shear stresses were for slip on the 11100 and the 13100 slip systems. Decompositions and dissociations of 1/2331 and 1/2111 dislocations were observed. The 1/2331 dislocation decomposes into 1/2111 and 110 dislocations during deformation at temperatures above 900°C. This decomposition prevents deformation by the 1/2331 dislocation at temperatures of 1200°C and above. HREM observations of the core of a 1/2331 dislocation revealed that it was dissociated out of the 13 glide plane after deformation at 900°C, while observations of the core of a 1/2111 dislocation after deformation at 1100°C revealed that it was dissociated by glide in the 110 plane. These core structures strongly affect the Peierls stress for glide of the 1/2331 and 1/2111 dislocations. Large climb dissociations of the 1/2111 and 1/2331 dislocations were also observed on the (001) plane, possibly resulting from the precipitation of Si vacancies on dislocations. A detailed comparison of these results with those of Umakoshi, Sakagami, Hirano and Yamane (1990) was undertaken by testing material provided by Umakoshi along (001) at 1000, 1300 and 1400°C and along (771) at 1100°C at a strain rate of 1 × 10−5/s . Marked differences were observed and explained by the dislocation substructure observed after deformation.
Download or read book Dislocation Structures in Single Crystal Tungsten and Tungsten Alloys written by Joseph R. Stephens and published by . This book was released on 1969 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Dislocation Structure of Subboundaries in Molybdenum Single Crystals written by Feng Tuan and published by . This book was released on 1968 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using the etch-figure technique, the authors have directly observed the dislocation structure of subboundaries in electron-beam zone-melted molybdenum single crystals. A thorough analysis of experimental results are given. The authors have observed various patterns indicating interactions of singular dislocations with subboundaries, in particular, 'steps' on the subboundaries induced by singular dislocations and also interactions of inclusions with subboundaries. The etch-figure method of observing dislocations is an effective means for the quantitative study of dislocation substructure in crystals. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1969 with total page 1508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Role of Dislocation Substructure During Class M and Exponential Creep written by Subramanium Varada Raj and published by . This book was released on 1995 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Creep in Molybdenum Single Crystals at Room Temperature written by Hans W. Wawrousek and published by . This book was released on 1957 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Initial Dislocation Structure and Dynamic Dislocation Multiplication in Mo Single Crystals written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied in order to investigate dislocation multiplication mechanisms in the early stages of plastic deformation. The initial dislocation density is in a range of 106 (almost equal to) 107 cm−2, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 108 (almost equal to) 109 cm−2, and the average jog height is also found to increase after compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. Both the jog height and length of link segment (between jogs) can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This dynamic dislocation multiplication source is subsequently verified by direct simulations of dislocation dynamics under stress to be crucial in the early stages of plastic deformation in Mo single crystals.
Download or read book Dislocation Multiplication in the Early Stage of Deformation in Mo Single Crystals written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied using transmission electron microscopy (TEM) techniques in order to investigate dislocation multiplication mechanisms in the early stage of plastic deformation. The initial dislocation density is in a range of 106 (almost equal to) 107 cm−2, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 108 (almost equal to) 109 cm−2, and the average jog height is also found to increase after compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. The jog height can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. The coalescence of superjogs results in an increase of both link length and jog height. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This ''dynamic'' dislocation multiplication source is suggested to be crucial for the dislocation multiplication in the early stage of plastic deformation in Mo.
Download or read book Research in Progress written by and published by . This book was released on 1970 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Topics in Crystallization written by Yitzhak Mastai and published by BoD – Books on Demand. This book was released on 2015-05-06 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: In nearly all process industries, crystallization is used at some stage as a method of production, purification or recovery of solid materials. In recent years, a number of new applications have also come to rely on crystallization processes such as the crystallization of nano and amorphous materials. The articles in this book have been contributed by some of the most respected researchers in this area and cover the frontier areas of research and developments in crystallization processes. Divided into three sections, this book provides the latest research developments in many aspects of crystallization including the crystallization of biological macromolecules and pharmaceutical compounds, the crystallization of nanomaterials and the crystallization of amorphous and glassy materials. This book is of interest to both fundamental research and practicing scientists and will prove invaluable to all chemical engineers and industrial chemists in process industries, as well as crystallization workers and students in industry and academia.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1970 with total page 1090 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recrystallization written by Krzysztof Sztwiertnia and published by BoD – Books on Demand. This book was released on 2012-03-07 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recrystallization shows selected results obtained during the last few years by scientists who work on recrystallization-related issues. These scientists offer their knowledge from the perspective of a range of scientific disciplines, such as geology and metallurgy. The authors emphasize that the progress in this particular field of science is possible today thanks to the coordinated action of many research groups that work in materials science, chemistry, physics, geology, and other sciences. Thus, it is possible to perform a comprehensive analysis of the scientific problem. The analysis starts from the selection of appropriate techniques and methods of characterization. It is then combined with the development of new tools in diagnostics, and it ends with modeling of phenomena.
Download or read book Russian Metallurgy written by and published by . This book was released on 1985 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:
