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Residual stress determination in a dissimilar weld overlay pipe by neutron diffraction
Woo, Wanchuck,Em, Vyacheslav,Hubbard, Camden R.,Lee, Ho-Jin,Park, Kwang Soo Elsevier 2011 Materials science & engineering. properties, micro Vol.528 No.27
<P><B>Highlights</B></P><P>► Determined residual stress distribution in a dissimilar weld overlay pipe. ► Consists of a ferritic (SA508), austenitic (F316L) steels, Alloy 182 consumable. ► Measured significant compression (−600MPa) near the inner wall of overlay. ► Validate integrity of the inner wall for the pressurized nozzle nuclear structure.</P> <P><B>Abstract</B></P><P>Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic ‘stress-free’ lattice spacing (<I>d</I><SUB><I>o</I></SUB>) was also obtained from both using a 2-mm width comb-like coupon. The results show significant changes in residual stresses from tension (300–400MPa) to compression (−600MPa) through the thickness of the dissimilar weld overlay pipe specimen.</P>
Crystallization of Precursors to Forsterite and Chromium-Doped Forsterite
Park, Dong Gon Martin, M. Hogan E. Ober, Christopher K. Burlitch, James M. Cavin, O. Burl Porter, Wallace D. Hubbard, Camden R. 숙명여자대학교 자연과학연구소 1994 자연과학논문집 Vol.- No.5
The pyrolysis and crystallization of poly(mathacrylate) precursors and xerogels of forsterite and chromiumdoped forsterite were studied by in situ high-temperature, dynamic X-ray diffraction and thermal analysis. For both types of precursor, crystallization of forsterite occurred at lower temperature when doped with chromium. Also, exotherms above 700℃ occurred 50℃ lower when chromium was present. When residual carbon in the xerogels was more than ∼1%, an unidentified crystalline intermediate phase formed at ∼800℃. Conversion of the intermediate phase to forsterite was faster than amorphous material. Thus, full crystallinity was attained at a lower temperature when the xerogels had some residual carbon.
Crystallization of Precursors to Forsterite and Chromium-Doped Forsterite
Park, Dong Gon,Martin, M. Hogan E.,Ober, Christopher K.,Burlitch, James M.,Cavin, O. Burl,Porter, Wallace D.,Hubbard, Camden R. 숙명여자대학교 자연과학연구소 1994 자연과학논문집 Vol.- No.5
The pyrolysis and crystallization of poly(mathacrylate) precursors and xerogels of forsterite and chromiumdoped forsterite were studied by in situ high-temperature, dynamic X-ray diffraction and thermal analysis. For both types of precursor, crystallization of forsterite occurred at lower temperature when doped with chromium. Also, exotherms above 700℃ occurred 50℃ lower when chromium was present. When residual carbon in the xerogels was more than ∼1%, an unidentified crystalline intermediate phase formed at ∼800℃. Conversion of the intermediate phase to forsterite was faster than amorphous material. Thus, full crystallinity was attained at a lower temperature when the xerogels had some residual carbon.