Download or read book Effect of fracture micromechanisms on crack growth resistance curves of irradiated zirconium 2 5 weight percent niobium alloy written by C. K. Chow and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Fracture Micromechanisms on Crack Growth Resistance Curves of Irradiated Zirconium 2 5 Weight Percent Niobium Alloy written by CK. Chow and published by . This book was released on 1988 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: J-integral resistance curves, determined from curved compact specimens of irradiated Zr-2.5Nb, show an unusual three-stage behavior. Immediately after initiation of stable crack extension, the crack growth resistance increases at a low rate, followed by a second stage in which the J-resistance (JR) curve rises relatively steeply. Finally, the J-resistance curve decreases its slope, eventually reaching an approximately constant (zero slope) value. To explain this behavior, a series of compact specimens were pulled to various stages of crack extension and carefully examined using metallographic techniques and scanning electron fractography. The authors conclude that the decrease in crack growth resistance due to irradiation is a consequence of shear localization behavior, and the three-stage JR curve is attributed to an abrupt transition from plane-strain conditions to the development of very flat shear lips. This peculiar shear-lip formation is shown to be a consequence of strain localization behavior.
Download or read book Zirconium in the Nuclear Industry Tenth International Symposium written by A. M. Garde and published by ASTM International. This book was released on 1994 with total page 805 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 1989 with total page 932 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crack Growth Resistance of Irradiated Zr 2 5Nb Pressure Tube Material at Low Hydrogen Levels written by RSW Shewfelt and published by . This book was released on 2001 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary factors influencing the crack growth resistance of irradiated Zr-2.5Nb pressure tube material at low concentrations of hydrogen/deuterium are reviewed. These factors include the initial characteristics of the material, which have brought about improvements in the toughness, and the operating conditions in reactor. The paper presents an update on the current status of this work using J-R curves. Such curves are determined from curved compact and rising-pressure burst test specimens at 250°C, i.e., the lower end of the operating temperature range. Some of the challenges encountered in assessing the crack growth toughness of this high-strength, thin-walled material are discussed. The role of chlorine, known to be responsible for the presence of Zr-Cl-C particles and preferential decohesion and fissuring, is also highlighted. The results from the curved compact specimens suggest a limiting level of chlorine above which no further significant degradation in crack growth resistance occurs. This level of chlorine is about 3 wt ppm for material having a low concentration of zirconium phosphide (P
Download or read book Mechanical Properties of Zircaloy 2 niobium oxygen Alloys written by A. E. Bibb and published by . This book was released on 1963 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Microstructural Factors on Irradiation Growth in Zirconium Niobium Alloys written by N. Sadaoka and published by . This book was released on 1989 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The irradiation growth mechanism of Zr-Nb alloys has been evaluated on the basis of a growth model in which point defect parameters obtained by molecular dynamics are used.
Download or read book Deformation of Irradiated Zirconium Niobium Alloys written by CE. Ells and published by . This book was released on 1974 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: This review summarizes the flow and fracture behavior of irradiated zirconium-niobium alloys. It is confined to the alloys currently used in power reactors, namely Zr-1.ONb, Zr-2.5Nb, and Zr-2.5Nb-0.5Cu, and of these, most of the literature deals with the Zr-2.5Nb alloy. Both before and after irradiation, the Zr-2.5Nb alloy has a good combination of strength and ductility; these properties have enabled reactor designers to replace Zircaloy with Zr-2.5Nb in applications where the superior in-reactor creep resistance of the latter alloy is important. The good ductility of the irradiated Zr-2.5Nb alloy, however, is dependent on the alloy remaining below the beta transus in the final stages of heat-treatment/fabrication before irradiation. Although there is much information on the deformation of the irradiated material relevant to reactor design, the basic understanding of the deformation is in an early stage of development.
Download or read book Tearing Crack Growth and Fracture Micro Mechanisms Under Micro Segregation in Zr 2 5 Nb Pressure Tube Material written by K. Kapoor and published by . This book was released on 2008 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the case of Zr-2.5%Nb pressure tube material, certain tramp elements (Cl, P, and C) have a deleterious effect on the fracture properties. In order to dramatically reduce the amount of these impurities, vacuum arc re-melting is adopted. The effect of the melting practice (double or quadruple) on the fracture properties of this material has been previously studied in detail. However, in these studies, the micro-mechanisms of fracture and the role of the trace impurities on crack initiation and propagation in the sub-critical regime were not investigated in detail. In the present study, the mechanisms operating during the three stages of crack growth, i.e., initiation, propagation and fracture, in the case of low toughness double melted material, are proposed based on a detailed study. In our observation, the tramp elements segregate in the form of fine stringers. In the regions away from the segregation, the material is found to be very ductile with the appearance of ligaments with high local plastic deformation before fracture. The presence of such ligaments on the fracture surface is an indication of fracture occurring in a transition zone (ductile to brittle). In the case of the failure in this transition region, both cleavage and ductile mechanisms can occur in the same specimen. In the transition region, near the upper shelf region, the initiation of the crack occurs by cleavage at a local discontinuity, but the toughness increases rapidly and crack propagation occurs in ductile manner by formation of microvoids. The crack front propagates finding the local discontinuities, leaving behind the unbroken regions with high toughness (ligaments). As the crack propagation continues and the crack face opens, the ligaments left well behind the crack tip rupture after the crack front moves further. The electron micro-beam analysis and X-ray mapping show a build-up of Cl concentration at the stringer sites. In the present analysis, the fracture behavior of double and quadruple melted Zr-2.5%Nb material is compared using a "tearing instability" criterion. Using this approach, an attempt is made to assess the enhanced safety margins, in terms of critical crack length, achieved by modification in the melting practice. First, an estimate from the small specimen J-R data was obtained. However, to obtain a realistic estimate for fracture under burst condition an appropriate scaling factor was applied.
Download or read book Effect of Irradiation and Irridiation Temperature on the Fracture Toughness of Cold worked Zr 2 5 Wt Percent Nb written by Atomic Energy of Canada Limited and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of neutron irradiation on tensile properties of the zirconium 2 5 weight per cent niobium alloy written by C. E. Ells and published by . This book was released on 1966 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The effects of dissolved oxygen upon the mechanical properties of zirconium 2 5 wt percent niobium alloy written by J. R. Kench and published by . This book was released on 1966 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fracture behaviour of the zirconium 2 5 wt percent niobium pressure tube written by R. R. Hosbons and published by . This book was released on 1967 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deformation of irradiated zirconium niobium alloys written by C. E. Ells and published by . This book was released on 1974 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of the Potential drop Method to Measurements of Hydrogen induced Sub critical Crack Growth in Zirconium 2 5 Wt Percent Niobium written by Atomic Energy of Canada Limited 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 effect of irradiation and irradiation temperature on the fracture toughness of cold worked zr 2 5 wt percent nb written by L. A. Simpson and published by . This book was released on 1984 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fracture toughness of zirconium hydride and its influence on the crack resistance of zirconium alloys written by L. A. Simpson and published by . This book was released on 1979 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
