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Plasma 분체육성용접법 (粉體肉盛熔接法) 에 의한 Al 합금의 표면후막 경화기술 개발
홍태환,문정훈,서창제,중전일박,송전복구 대한금속재료학회(대한금속학회) 1992 대한금속·재료학회지 Vol.30 No.12
A new Plasma Transferred Arc(PTA) hardfacing process has been developed to obtain an overlay weld metal having excellent wear resistance. Effect of Ti, Ni and Cu metal powders addition on the surface characteristics of Aluminum alloy 5083 has been investigated with PTA process. Optimum overlaying condtions under which bead appearance is superior and porosities in overlaid metal are lesser are determined. This paper describes the results of tests on the performance of the overlay weld metal. The results are as fallow: (1) The mean hardness of the overlay weld metal is adjustable from Hv200 to Hv600 by PTA process. (2) Concerning defect of overlaid metals, blow holes were seen in Ni and Ti addition. Residual gas contents in blow hole for overlaid metals were confirmed as mainly H₂and a little of N₂. (3) The welding performance of this process is improved by use of DCRP plasma arc, which performs cleaning action on the base metal and weld metal. These results is an increase in welding efficiency. (4) The results of wear tests show that the weld metal has high wear resistance by the PTA process.
H. Fujiwara,Y. Nakatani,H. Aratani,Y. Kanai-Nakata,K. Yamagami,S. Hamamoto,T. Kiss,A. Sekiyama,A. Tanaka,T. Ebihara,Y. Saitoh 한국물리학회 2023 새물리 Vol.73 No.12
We have performed the soft x-ray absorption spectroscopy (XAS) on the heavy fermion superconductor CeNi₂Ge₂ to examine the local 4f electronic structures. The XAS spectra are qualitatively explained by the ionic calculation, indicating the localized character of the 4f states, while the sizable cf-hybridization effects are also observed in the XAS spectra and those magnetic circular dichroism. In addition, the temperature dependence of linear dichroism (LD) in the XAS spectra indicates that the ground state symmetry is Γ<SUB>7</SUB>, and the excited states with Γ<SUB>6</SUB> symmetry is above 390 K.
K. H. Song,Y. D. Chung,K. Nakata 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.3
This study was conducted to investigate the microstructure and mechanical properties of friction stir lap joints. Monel 400 and Inconel 600 were selected as the experimental materials, and friction stir welding was carried out at a tool rotation speed of 200 rpm and welding speed of 100 mm/min. The application of friction stir welding to Monel 400 effectively reduced the grain size in the stir zone; the average grain size of Monel 400 was reduced from 11.9 μm in the base material to 4.2 μm in the stir zone, which resulted in an improvement in the mechanical properties of the stir zone. The joint interface between Monel 400 and Inconel 600 showed a relatively sound weld without grooves or cracks, and only a small amount of voids with a size of 0.5 μm; however, no intermetallic compounds were observed in the lap jointed interface. Moreover, the hook on the advancing side of Monel 400 was formed from Inconel 600, which contributed to maintenance of the tensile strength. The evolution of microstructures and mechanical properties of friction stir lap jointed Monel 400 and Inconel 600 are also discussed herein.
Hough, L. E.,Jung, H. T.,Krü,erke, D.,Heberling, M. S.,Nakata, M.,Jones, C. D.,Chen, D.,Link, D. R.,Zasadzinski, J.,Heppke, G.,Rabe, J. P.,Stocker, W.,Kö,rblova, E.,Walba, D. M.,Glaser, M. A. American Association for the Advancement of Scienc 2009 Science Vol.325 No.5939
<P>In the formation of chiral crystals, the tendency for twist in the orientation of neighboring molecules is incompatible with ordering into a lattice: Twist is expelled from planar layers at the expense of local strain. We report the ordered state of a neat material in which a local chiral structure is expressed as twisted layers, a state made possible by spatial limitation of layering to a periodic array of nanoscale filaments. Although made of achiral molecules, the layers in these filaments are twisted and rigorously homochiral--a broken symmetry. The precise structural definition achieved in filament self-assembly enables collective organization into arrays in which an additional broken symmetry--the appearance of macroscopic coherence of the filament twist--produces a liquid crystal phase of helically precessing layers.</P>