High temperature deformation of VGF melt-textured YBCO

The deformation behavior of melt-textured YBCO prepared by the vertical gradient freeze (VGF) method was investigated by high temperature deformation experiments at temperatures ranging from 850 C to 950 C. The experiments were performed in an atmosphere of pure oxygen under uniaxial pressure with constant strain rates in the range from 1 x 10"-"5 s"-"1 to 5 x 10"-"4 s"-"1. An analysis of the dependence of the steady state flow stress on the strain rate and the deformation temperature reveals that the predominant deformation mechanism is dislocation glide and climb controlled by climb at Y-211 particles and that no significant grain boundary sliding occurs. Furthermore, TEM observations of deformed and undeformed samples support a deformation mechanism based on dislocation movement. The total fracture strain, however, does not depend on the temperature or strain rate. SEM investigations of the fracture faces of samples deformed unti fracture reveal that fracture does not occur within the Y-123 matrix but along platelet boundaries. An improvement of the fracture behavior is expected by introducing large Y-211 particles interconnecting neighboring platelets. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(67,33) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Entwicklung einer Technologie zur kontinuierlichen HTSL-Beschichtung zylindrischer Oberflaechen. Hier: Teilbericht ZfW Abschlussbericht

Available from TIB Hannover: DtF QN1(49,51) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Praezisionsbearbeitung mit Festkoerperlasern: Fuegen. Teilprojekt: Schweissen von Werkstoffen bzw. Werkstoffkombinationen mit geringer Schweissneigung Abschlussbericht

The aim of this project was to evaluate the weldability of materials which are difficult to joint by conventional methods using a pulsed Nd:YAG laser. Because high strength aluminium alloys found increased interest for applications in the automobile and aircraft industry the research was focussed on the welding of the age hardenable alloys AlMgSi1, AlCuMg1 and AlZnMgCu1,5. Welding was conducted with and without filter. Only for the alloy AlZnMgCu1,5 the use of a filler was essential to achieve a good joint. The tensile strength of AlMgSi1 joints reached 64% of the value for the base material thus exceeding the tensile strength of TIG- and WIG-welded joints. With a subsequent heat treatment (solutionizing and age hardening) the tensile strength was increased up to 71%. For the alloy AlCuMg1 values of 61 and 86% respectively were achieved. Welding with filler led to a further increase of the tensile strength (approximately 10% compared to the values of joints welded without filler). For AlMgSi1 an AlSi12 filler was best whereas for AlCuMg1 and AlZnMgCu1,5 the addition of AlMg5 led to better results. The fatigue strength of AlMgSi1 and AlCuMg1 joints drops to values 40 to 60% below those of the base material. Considering that the joints were tested in the as-welded condition this decrease is not dramatical. Moreover, the variance is low. However, the AlZnMgCu1,5 joints were notch-sensitive and due to an extreme variance no Woehler curve could be determined. Therefore Nd:YAG laser welded joints of this alloy cannot be recommended for applications were fatigue resistance is required. (orig.)SIGLEAvailable from TIB Hannover: F99B841+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Batch production of high-quality-customized-shaped-monolithic HTSC Final report

Customized shaped monolithic YBCO were preduced applying the TSMG method. These HTSC are single-domain monoliths according to optical microscopy, X-ray diffraction, neutron diffraction as well as hall probe measurements. The trapped magnetic induction of such a single-domain monolith at 77 K usually well exceeds 600 mT. An external scan of the remanent induction of a 17 mm x 17 mm x 8 mm large-single-domain sample at 77 K yields a record value of 865 mT. The zfc levitation forces of standard samples (38 mm x 38 mm x 12 mm) at 77 K typically amount to 60-70 N. Actually, 16 units with these standard sizes of the quality described can be produced in one batch. Furthermore, YBCO monoliths with diameters up to 130 mm were successfully melt-textured. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(67,32) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Kryobehaelter mit HTSL-Lagerung. Aufbau und Eigenschaften von selbststabilen HTSL-PM Magnetlagern fuer Kryobehaelter

SIGLEAvailable from TIB Hannover: DtF QN1(70,51) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Grundlegende Untersuchungen zur Zuechtung versetzungsarmer GaAs-Substratkristalle mit dem vertikalen Gradient Freeze Verfahren Forschungsbericht/Abschlussbericht

Available from TIB Hannover: F98B91+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

LH_2-Kryobehaelter mit HTSL-Lagerung des Innentanks

SIGLEAvailable from TIB Hannover: DtF QN1(68,19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman