Download or read book Thermally Activated Deformation in alpha iron written by and published by . This book was released on 1979 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Temperature and Strain Rate of Thermally Activated Deformation in High Purity Alpha Iron written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure Evolution in Alpha Iron During High Temperature Tensile Deformation written by Phi Hùng Xuân Thành and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructural evolution of alpha iron under tensile deformation at high temperature (T[subscript H]> 0.5) and slow strain-rate (10−5s−1 to 10−5s−1) was investigated. The impetus for this study was the recent observation of Dynamic Abnormal Grain Growth (DAGG) in pure molybdenum under the same testing conditions. A high temperature tensile testing system was refurbished and assembled for this study. The testing system consists of an Centorr 2229 furnace system mounted on an Instron 1331 load frame. I designed the tensile grip and programmed the testing program to obtain data in the stress and strain regime of interest. Testing were done at both UC Davis and Los Alamos National Labs (LANL). Metallography techniques and electron backscattering diffraction (EBSD) technique in a scanning electron microscope were used to characterize the samples after testing. In addition to normal tensile tests at constant strain-rates where DAGG is proposed to occur, a series of strain-rate change tests were designed and performed. Strain-rate change tests were employed to extract activation area information that provided insight into the active mechanism of deformation of the material in addition to the information obtained from analysis of the stress-strain curve and the microstructure via optical microscopy and EBSD. The obtained stress-train curve data were compared with the stress-strain curves data in the literature for alpha iron in similar regime of deformation indicating that the dominant mechanism of deformation is dynamic recovery. The comparison includes past stress-strain curves and the data recorded in the Ashby Map. Optical and EBSD analysis showed that normal grain growth occurred in alpha iron during this testing regime. This lack of grain boundary pinning by impurity differs from that observed in Mo that exhibited DAGG. Activation area analysis showed that the activation area values of Fe are consistent with friction drag from the lattice being the active deformation mechanism. The same activation area analysis reveals that the active mechanism of deformation in the Mo material that exhibited DAGG is impurity drag. These analyses reveal the microstructure evolution of pure alpha iron and provide thought about the difference between Fe and Mo. Although both Fe and Mo have a BCC structure and undergo dynamic recovery for the processing conditions considered, DAGG did not occur in pure Fe. Dynamic recovery and normal grain growth occurred in Fe instead; there was no grain boundary pinning.
Download or read book Modelling the Plastic Deformation of Iron written by Zhiming Chen and published by KIT Scientific Publishing. This book was released on 2014-07-31 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1/2111 screw dislocations in bcc iron are studied by atomistic simulations. An analytical yield criterion captures correctly the non-Schmid plastic behavior. A model Peierls potential develops a link between the atomistic modeling at 0 K and the thermally activated dislocation motion. All predicted features agree well with experimental observations. This work establishes a consistent bottom-up model that provides an insight into the microscopic origins of the plastic behavior of bcc iron.
Download or read book High Temperature Deformation and Recrystallisation of Alpha Iron written by Graham Glover and published by . This book was released on 1969 with total page 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 1975 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Prestrain Temperature on the Strain Aging of Alpha iron written by E. LAUTENSCHLAGER and published by . This book was released on 1961 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yield point measurements were made on polycrystalline specimens of alpha-iron deformed various amounts at 77, 195 and 273 K; aged; and redeformed at 77, 195, and 273 K. When the prestrain temperature is lower than that subsequent to aging, the yield point return is suppressed relative to specimens deformed at the same temper-ATURE BOTH BEFORE AND AFTER AGING. The degree of suppression is a function of both the magnitude of prestrain at the lower temperature and the difference between the deformation temperatures before and after aging. It is proposed that the suppression is caused by the formation of dislocation barriers during the initial low temperature deformation. The aging kinetics of polycrystalline alpha-iron wires deformed at 77 or 303 K were studies at 44 and 64 C using internal friction measurements. No change was noted as a result of the difference in prestrain temperature. (Author).
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1964 with total page 1528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermally Activated Process of Deformation in FCC Spinodally Modulated Structure written by Tong-Chang Lee and published by . This book was released on 1982 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dose Rate Annealing and Stress relaxation Studies of Radiatino Hardening in Iron written by and published by . This book was released on 1967 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermally Activated Mechanisms in Crystal Plasticity written by D. Caillard and published by Elsevier. This book was released on 2003-09-08 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: KEY FEATURES: - A unified, fundamental and quantitative resource. The result of 5 years of investigation from researchers around the world - New data from a range of new techniques, including synchrotron radiation X-ray topography provide safer and surer methods of identifying deformation mechanisms - Informing the future direction of research in intermediate and high temperature processes by providing original treatment of dislocation climb DESCRIPTION: Thermally Activated Mechanisms in Crystal Plasticity is a unified, quantitative and fundamental resource for material scientists investigating the strength of metallic materials of various structures at extreme temperatures. Crystal plasticity is usually controlled by a limited number of elementary dislocation mechanisms, even in complex structures. Those which determine dislocation mobility and how it changes under the influence of stress and temperature are of key importance for understanding and predicting the strength of materials. The authors describe in a consistent way a variety of thermally activated microscopic mechanisms of dislocation mobility in a range of crystals. The principles of the mechanisms and equations of dislocation motion are revisited and new ones are proposed. These describe mostly friction forces on dislocations such as the lattice resistance to glide or those due to sessile cores, as well as dislocation cross-slip and climb. They are critically assessed by comparison with the best available experimental results of microstructural characterization, in situ straining experiments under an electron or a synchrotron beam, as well as accurate transient mechanical tests such as stress relaxation experiments. Some recent attempts at atomistic modeling of dislocation cores under stress and temperature are also considered since they offer a complementary description of core transformations and associated energy barriers. In addition to offering guidance and assistance for further experimentation, the book indicates new ways to extend the body of data in particular areas such as lattice resistance to glide.
Download or read book Nuclear Fuels and Materials Development Program Summary for 1965 written by Ruth Ann Newman and published by . This book was released on 1966 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Biweekly Cryogenics Current Awareness Service written by and published by . This book was released on 1976 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Low Temperature Thermally Activated Deformation Mechanisms for BCC Magnesium lithium aluminum Alloy written by Mohamed Osama Abo El-Fotoh and published by . This book was released on 1967 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dislocation Mechanics of Metal Plasticity and Fracturing written by Ronald W. Armstrong and published by MDPI. This book was released on 2020-11-03 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The modern understanding of metal plasticity and fracturing began about 100 years ago, with pioneering work; first, on crack-induced fracturing by Griffith and, second, with the invention of dislocation-enhanced crystal plasticity by Taylor, Orowan and Polanyi. The modern counterparts are fracture mechanics, as invented by Irwin, and dislocation mechanics, as initiated in pioneering work by Cottrell. No less important was the breakthrough development of optical characterization of sectioned polycrystalline metal microstructures started by Sorby in the late 19th century and leading eventually to modern optical, x-ray and electron microscopy methods for assessments of crystal fracture surfaces, via fractography, and particularly of x-ray and electron microscopy techniques applied to quantitative characterizations of internal dislocation behaviors. A major current effort is to match computational simulations of metal deformation/fracturing behaviors with experimental measurements made over extended ranges of microstructures and over varying external conditions of stress-state, temperature and loading rate. The relation of such simulations to the development of constitutive equations for a hoped-for predictive description of material deformation/fracturing behaviors is an active topic of research. The present collection of articles provides a broad sampling of research accomplishments on the two subjects.
Download or read book Thermal Fatigue of Ductile Materials written by Francis J. Clauss and published by . This book was released on 1958 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was made of the changes in the stress-rupture life, ductility, hardness, and microstructure of S-816 and Inconel 550 specimens that had been exposed to varying amounts and conditions of thermal fatigue.
