Download or read book Amorphization Kinetics of Zr Cr Fe 2 Under Ion Irradiation written by Arthur T. Motta and published by Chalk River, Ont. : Reactor Materials Research Branch. This book was released on 1994-01-01 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amorphization Kinetics of Zr Cr Fe 2 Under Ion Irradiation written by and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin foils of Zircaloy-4 were irradiated with 350 KeV 4°Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300--650 K. The irradiation-induced amorphization of the intermetallic precipitates Zr (Cr; Fe)2 and Zr2 (Ni, Fe) was studied in-situ. For Zr (Cr, Fe)2 precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr2 (Ni, Fe) precipitates it was found that amorphization occurred at 550 and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in context of previous neutron and electron irradiations and likely amorphization mechanisms are proposed.

Download or read book Amorphization Kinetics of Zr Cr Fe sub 2 Under Ion Irradiation written by and published by . This book was released on 1992 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin foils of Zircaloy-4 were irradiated with 350 KeV [sup 40]Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300--650 K. The irradiation-induced amorphization of the intermetallic precipitates Zr (Cr; Fe)[sub 2] and Zr[sub 2] (Ni, Fe) was studied in-situ. For Zr (Cr, Fe)[sub 2] precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr[sub 2] (Ni, Fe) precipitates it was found that amorphization occurred at 550 and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in context of previous neutron and electron irradiations and likely amorphization mechanisms are proposed.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book In Situ HVEM Studies of Phase Transformation in Zr Alloys and Compounds Under Irradiation written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The High Voltage Electron Microscope (HVEM)/Tandem facility at Argonne National Laboratory has been used to conduct detailed studies of the phase stability and microstructural evolution in zirconium alloys and compounds under ion and electron irradiation. Detailed kinetic studies of the crystalline-to-amorphous transformation of the intermetallic compounds Zr[sub 3](Fe[sub 1-x]Ni[sub x]), Zr(Fe[sub 1-x], Cr[sub x])[sub 2], Zr[sub 3]Fe, and Zr[sub 1.5] Nb[sub 1.5] Fe, both as second phase precipitates and in bulk form, have been performed using the in-situ capabilities of the Argonne facility, under a variety of irradiation conditions (temperature, dose rate). Results include a verification of a dose rate effect on amorphization and the influence of material variables (stoichiometry x, presence of stacking faults, crystal structure) on the critical temperature and on the critical dose for amorphization. Studies were also conducted of the microstructural evolution under irradiation of specially tailored binary and ternary model alloys. The stability of the[omega]-phase in Zr-20%Nb under electron and Ar ion irradiation was investigated as well as the[beta]-phase precipitation in Zr-2.5%Nb under Ar ion irradiation. The ensemble of these results is discussed in terms of theoretical models of amorphization and of irradiation-altered solubility.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amorphization Kinetics of Zr sub 3 Fe Under Electron Irradiation written by and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: 0.9 MeV electron irradiations were performed at 28--220 K in a high-voltage electron microscope (HVEM). By measuring onset, spread and final size of the amorphous region, factoring in the Guassian distribution of the beam, a kinetic description of the amorphization in terms of dose, dose rate and temperature was obtained. The critical temperature for amorphization by electron irradiation was found to be ∼220 K, compared to 570--625 K for 4°Ar ion irradiation. Also, the dose-to-amorphization increased exponentially with temperature. Results indicated that the rate of growth of the amorphous region under the electron beam decreased with increasing temperature and the does-to-amorphization decreased with increasing dose rate. The size of the amorphous region saturated after a region dose, the final size decreasing with increasing temperature, and it was argued that this is related to the existence of a critical dose rate, which increased with temperature, below which no amorphization occurred. The above observations can be understood in the framework of the kinetics of damage accumulation under irradiation.

Download or read book Irradiation induced Phase Transformations in Zirconium Alloys written by and published by . This book was released on 1994 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: 4°Ar and 2°9Bi ion irradiations of Zr3Fe were performed at 35--725 K using 15-1500 keV ions. Results are presented on role of deposited-energy density on nature of the damaged regions in individual cascades produced by ion bombardment of Zr3Fe. Comparison is also made between irradiation-induced amorphization of Zr3Fe during electron irradiation and under ion bombardments. Dependence of damage production on incident electron energy in Zr3Fe was also determined. Preliminary results are also discussed for amorphization of ZrFe2, Zr(Cr, Fe)2 and ZrCr2 by electron irradiation. Results of a recent investigation on amorphization of Zr(Cr, Fe)2 and Zr2(Ni, Fe) precipitates in Zircaloy-4 are discussed in context of previous experimental results of neutron and electron irradiations and likely amorphization mechanisms are proposed.

Download or read book A Simple Kinetic Model of Zircaloy Zr Fe Cr 2 Precipitate Amorphization During Neutron Irradiation written by and published by . This book was released on 1999 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: At neutron flux levels typical for Zircaloy fuel cladding in commercial power reactors, there is insufficient thermal energy below about 600 K to maintain long-range order in hexagonal close packed (hcp) Zr(Fe, Cr)2 precipitates, and these Laves-phase intermetallics gradually become amorphous. The transformation is homogeneous with no change in composition at low temperatures, but above 500 K an amorphous zone containing only 10 at% Fe grows inward from the periphery as Fe moves outward to the adjacent alloy matrix. The shrinking central cores of Zr(Fe, Cr)2 precipitates in Zircaloy-4 remain crystalline, while in Zircaloy-2 these precipitates quickly undergo partial transformation and the low-Fe amorphous front advances into a random mixture of amorphous and crystalline regions, each with the original composition. Above 600 K, the Zr(Fe, Cr)2 precipitates tend to retain both their hcp structure and original chemical composition. These observations suggest that a dynamic competition between kinetic excitation to an amorphous state and thermal recrystallization makes some fraction of the Fe atoms available for flux-assisted diffusion to the alloy matrix by displacing them from hcp lattice positions into metastable, probably interstitial, sites. With one set of kinetic constants, a simple analytic representation of these processes accurately predicts precipitate amorphization as a function of neutron flux, temperature, and time for either Zircaloy-2 or -4. By implication, over the composition range of interest, hcp Zr(Fe, Cr)2 is most stable thermodynamically with about 33 at% Fe, typical of Zircaloy-2, but amorphous Zr(Fe, Cr)2 has the smallest activation energy for recrystallization with the slightly higher Fe content typical of Zircaloy-4.

Download or read book Ordering and Disordering in Alloys written by A.R. Yavari and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the European Workshop on Ordering and Disordering held in Grenoble, France, 10-12 July 1991.

Download or read book Beam Solid Interactions Volume 279 written by Michael Nastasi and published by . This book was released on 1993-08-09 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.

Download or read book Amorphization kinetics of Zr3Fe under electron irradiation written by Chalk River Nuclear Laboratories. Reactor Materials Research Branch and published by Chalk River, Ont. : Reactor Materials Research Branch, Chalk River Laboratories. This book was released on 1994 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Zirconium in the Nuclear Industry written by George P. Sabol and published by ASTM International. This book was released on 1996 with total page 907 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 Metals Abstracts written by and published by . This book was released on 1996 with total page 1628 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amorphization Kinetics of Zr3Fe Under Electron Irradiation written by and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: 0.9 MeV electron irradiations were performed at 28--220 K in a high-voltage electron microscope (HVEM). By measuring onset, spread and final size of the amorphous region, factoring in the Guassian distribution of the beam, a kinetic description of the amorphization in terms of dose, dose rate and temperature was obtained. The critical temperature for amorphization by electron irradiation was found to be (approximately)220 K, compared to 570--625 K for 4°Ar ion irradiation. Also, the dose-to-amorphization increased exponentially with temperature. Results indicated that the rate of growth of the amorphous region under the electron beam decreased with increasing temperature and the does-to-amorphization decreased with increasing dose rate. The size of the amorphous region saturated after a region dose, the final size decreasing with increasing temperature, and it was argued that this is related to the existence of a critical dose rate, which increased with temperature, below which no amorphization occurred. The above observations can be understood in the framework of the kinetics of damage accumulation under irradiation.

Download or read book Phase Transformations written by Srikumar Banerjee and published by Elsevier. This book was released on 2010-05-31 with total page 837 pages. Available in PDF, EPUB and Kindle. Book excerpt: The terms phase transitions and phase transformations are often used in an interchangeable manner in the metallurgical literature. In Phase Transformations, transformations driven by pressure changes, radiation and deformation and those occurring in nanoscale multilayers are brought to the fore. Order-disorder transformations, many of which constitute very good examples of continuous transformations, are dealt with in a comprehensive manner. Almost all types of phase transformations and reactions that are commonly encountered in inorganic materials are covered and the underlying thermodynamic, kinetic and crystallographic aspects elucidated. - Shows readers the advancements in the field - due to enhanced computing power and superior experimental capability - Drawing upon the background and the research experience of the authors, bringing together a wealth of experience - Written essentially from a physical metallurgists view point