Download or read book The Role of Grain Boundary Chemistry and Structure in the Environmentally assisted Intergranular Cracking of Nickel base Alloys written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Role of Grain Boundary Chemistry and Structure in the Environmentally assisted Intergranular Cracking of Nickel base Alloys Progress Report August 1 1991 July 31 1992 written by and published by . This book was released on 1992 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress corrosion cracking tests in constant extension rate tensile (CERT) and constant load tensile (CLT) tests were conducted on Ni-xCr- 9Fe-yC in Ar, water, and a LiOH-boric acid solution. Cr and C improve the resistance of Ni-base alloys to IG cracking in both Ar and water at 360C. Since creep plays a role in IG cracking, one possible explanation for the role of the environment involves its effect on the creep. Experiments were conducted on the role of C in the deformation behavior and failure mode of Ni-16Cr-9Fe. Constant load experiments were conducted on Ni-16Cr-9Fe to determine if the CLT test is more aggressive than CERT. The electron backscattering technique in a SEM is being developed in order to extend the IG cracking studies to grain sizes typical of commercial alloys, 20-30 microns.
Download or read book The Role of Grain Boundary Chemistry and Structure in the Environmentally assisted Intergranular Cracking of Nickel base Alloys Progress Report December 1 1990 November 31 1993 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress focused on (1) determination of the role of C and Cr on deformation and IG cracking behavior of Ni-(5--30)Cr-9Fe, (2) determination of the effect of grain boundary misorientation on IG cracking behavior, (3) construction of an electron backscattering pattern (EBSP) imaging system, (4) determination of effect of the environment on creep and cracking, and (5) characterization of the surface film. Results showed that both C and Cr are potent solid solution strengtheners which can reduce the steady state creep rate at 360[degree]C by several orders of magnitude. Intergranular cracking of 100 [mu]m grain samples of high purity Ni-16Cr-9Fe at 360[degree]C occurs by formation of grain boundary voids and interlinkage, driven by dislocation creep in the matrix. Creep experiments in primary water at 360[degree]C and an applied cathodic potential show that the creep rate is increased by an order of magnitude over that in Ar and the percent IG fracture increases as well. Oxide film composition and thickness is a sensitive function of the C content, increasing in thickness and Ni(OH)[sub 2] content with increase in C or decrease in Cr to 5 wt%. Thermomechanical treatments along with electron channeling pattern (ECP) analysis wee used to create and index, samples with enhanced fractions of coincident site lattice boundaries (CSLBs). Constant extension rate tensile (CERT) experiments on samples with a high percentage of CSLBs showed IG cracking compared with general high angle boundaries. However, these experiments were conducted on grain sizes of 300 [mu]m, while commercial material is an order of magnitude smaller. An electron backscattering pattern imaging system has been constructed for an environmental scanning electron microscope which can image grains below [mu]m. The system has been successfully benchmarked against results from ECP analysis.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1989 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book D R D A Reporter written by and published by UM Libraries. This book was released on 1991 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Download or read book INIS Atomindex written by and published by . This book was released on 1995 with total page 640 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 1995 with total page 1602 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book UNDERSTANDING THE MECHANISMS CONTROLLING ENVIRONMENTALLY ASSISTED INTERGRANULAR CRACKING OF NICKEL BASE ALLOYS written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Creep and IG cracking of nickel-base alloys depend principally on two factors--the deformation behavior and the effect of the environment. We have shown that both contribute to the observed degradation in primary water. The understanding of cracking does not lie wholly within the environmental effects arena, nor can it be explained only by intrinsic mechanical behavior. Rather, both processes contribute to the observed behavior in primary water. In this project, we had three objectives: (1) to verify that grain boundaries control deformation in Ni-16Cr-9Fe at 360 C, (2) to identify the environmental effect on IGSCC, and (3) to combine CSLBs and GBCs to maximize IGSCC resistance in Ni-Cr-Fe in 360 C primary water. Experiments performed in hydrogen gas at 360 C confirm an increase in the primary creep rate in Ni-16Cr-9Fe at 360 C due to hydrogen. The creep strain transients caused by hydrogen are proposed to be due to the collapse of dislocation pile-ups, as confirmed by observations in HVEM. The observations only partially support the hydrogen-enhanced plasticity model, but also suggest a potential role of vacancies in the accelerate creep behavior in primary water. In high temperature oxidation experiments designed to examine the potential for selective internal oxidation in the IGSCC process, cracking is greatest in the more oxidizing environments compared to the low oxygen potential environments where nickel metal is stable. In Ni-Cr-Fe alloys, chromium oxides form preferentially along the grain boundaries, even at low oxygen potential, supporting a potential role in grain boundary embrittlement due to preferential oxidation. Experiments designed to determine the role of grain boundary deformation on intergranular cracking have established, for the first time, a cause-and-effect relationship between grain boundary deformation and IGSCC. That is, grain boundary deformation in Ni-16Cr-9Fe in 360 C primary water leads to IGSCC of the deformed boundaries. As well, the activation energy for grain boundary diffusion driving grain boundary deformation, QHAB=231 kJ/mole, is comparable to that for IGSCC initiation (212-241 kJ/mole), suggesting that grain boundary deformation is also the rate limiting factor for crack initiation. The resistance to IGSCC of Ni-16Cr-9Fe can be maximized by combining grain boundary misorientation with grain boundary carbide precipitation. Taken separately, an increased coincident site lattice fraction, and precipitation of grain boundary carbides increase the resistance to IGSCC initiation in 360 C primary water. In combination, the increase in resistance is greater than either of the effects taken separately. The grain boundary carbides tend to prefer the high angle boundaries, and thus, the combined treatment affords greater resistance by protecting a higher fraction of grain boundaries than either taken separately.
Download or read book Meeting of Board of Regents written by University of Michigan. Board of Regents and published by . This book was released on 1996-02 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993 with total page 1094 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1991 with total page 1280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1994 with total page 1828 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
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 Intergranular Stress Corrosion Cracking and Selective Internal Oxidation of Ni Cr Fe Alloys in Hydrogenated Steam written by Brent M. Capell and published by . This book was released on 2005 with total page 838 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Role of Grain Boundary Chemistry and the Environment on Intergranular Fracture written by R. M. Latanision and published by . This book was released on 1980 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this discussion the influence of grain boundary segregates and their interaction with the environment will be discussed with particular reference to hydrogen-induced intergranular embrittlement. Many of the elements which are found segregated at grain boundaries (i.e., the metalloid elements) are catalyst poisons for the hydrogen evolution reaction in electrolytes and, hence, stimulate hydrogen absorption. The use of glassy metal alloys (transition metal-metalloid type) as grain boundary analogs in studying hydrogen absorption and permeation is explored. Likewise, permeation experiments which distinguish between lattice, grain boundary and dislocation transport mechanisms will be discussed. (Author).
