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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 1 (1968), S. 328-328 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 5 (1986), S. 101-102 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1988), S. 243-244 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 4 (1969), S. 929-932 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1972), S. 131-141 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract When polyethylene single crystals are mounted on a substrate less rigid than the usual evaporated carbon, they undergo considerable dimensional changes in the electron beam. In particular, crystals mounted on collodion expand by 22±2% in every direction in the plane of the lamellae. No induction period is observed and the expansion continues after all crystalline order has been destroyed. Since irradiation increases the density of bulk polyethylene, it is presumed that the lamellae become thinner as they expand. A similar but lesser expansion occurs on irradiation in the electron microscope at liquid helium temperatures, and when crystals are mounted on formvar films. In a solution grown lamellar crystal of polyethylene, most of each molecule is straight and aligned along thec axis, which is nearly perpendicular to the plane of the lamella. Radiation damage in the electron microscope introduces disorder, and these results imply that the effect of this disorder is to reduce the mean molecular dimension alongc, and increase it in the plane perpendicular toc. Polymer chains are generally highly oriented in crystalline regions, so this qualitative explanation would imply similar effects in other systems. These effects have important implications for the contrast observed in the electron microscopy of polymers.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1972), S. 131-141 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract When polyethylene single crystals are mounted on a substrate less rigid than the usual evaporated carbon, they undergo considerable dimensional changes in the electron beam. In particular, crystals mounted on collodion expand by 22±2% in every direction in the plane of the lamellae. No induction period is observed and the expansion continues after all crystalline order has been destroyed. Since irradiation increases the density of bulk polyethylene, it is presumed that the lamellae become thinner as they expand. A similar but lesser expansion occurs on irradiation in the electron microscope at liquid helium temperatures, and when crystals are mounted on formvar films. In a solution grown lamellar crystal of polyethylene, most of each molecule is straight and aligned along thec axis, which is nearly perpendicular to the plane of the lamella. Radiation damage in the electron microscope introduces disorder, and these results imply that the effect of this disorder is to reduce the mean molecular dimension alongc, and increase it in the plane perpendicular toc. Polymer chains are generally highly oriented in crystalline regions, so this qualitative explanation would imply similar effects in other systems. These effects have important implications for the contrast observed in the electron microscopy of polymers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 7 (1972), S. 427-434 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The transverse rupture strength of hot-pressed and annealed composites of magnesium oxide and dispersed metallic phases (nickel, iron, cobalt) increases with increasing volume fraction of metal and annealing temperature. The strengthening effect of the metal is attributed to an inhibition of grain growth while flaw healing occurs during the annealing of the composites. The strength of magnesium oxide hot-pressed with nickel fibres is not affected by the volume fraction of fibre or the annealing temperature, and is comparable to the strength of porous magnesia. However, the work of fracture, though insensitive to heat-treatment, increases by at least two orders of magnitude for a moderate volume fraction of randomly oriented fibres. Mechanisms of energy absorption during the fracture of composites containing weakly bonded, non-aligned fibres are discussed. They include the work done in plastically deforming the fibre as it is withdrawn from its socket. It is concluded that this mechanism may be of importance in composites containing very weakly bonded ductile fibres.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 8 (1973), S. 1012-1022 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Polypropylene and high-density polyethylene, oriented by hot drawing, have been tensile testedin situ in a low angle X-ray camera. Two orientations of polypropylene,Θ 0=31° andΘ 0=60°, and one orientation of polyethylene,Θ 0=30°, were examined. (Θ 0 is the initial angle between the tensile axis and the molecular axis.) Low-angle and wide-angle X-ray patterns were taken at successive stages of increasing strain up to approximately 100%. The rotations of the molecular axis and lamellar normal for both materials oriented nearΘ 0=30° were quantitatively consistent with predominantly intermolecular shear, occurring within the lamellae. In the case of polypropylene, it is proposed that small amounts of interlamellar and interfibrillar shear were also present. AtΘ 0=60°, the polypropylene was shown to deform by void opening or fibril separation, followed by intermolecular shear. The behaviour of polypropylene was consistent with the yield criterion based on a fibre reinforced composite model which was presented in a previous paper [1].
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 8 (1973), S. 1238-1246 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Sapphire filament oriented within 2 1/2° of the crystallographic c-axis underwent creep by a mechanism other than slip on the basal planes at temperatures above 1600° C. There was a stress below which creep could not be detected; this decreased from 180 MNm−2 at 1600° C to 65 MNm−2 at 1800° C. The total tensile strain obtained never exceeded 5%. Fracture occurred during a linear stage of creep in which the stress exponent of the strain-rate was approximately 6. The creep mechanism appeared to be slip on {20¯2¯1} 〈01 T2〉 (morphological unit cell). A filament in which the c-axis lay at 6° to the filament axis deformed by localized basal slip. The accompanying local latice rotations produced fracture at a small overall strain, usually less than 0.5%. The results demonstrate extreme anisotropy of creep in sapphire crystals.
    Type of Medium: Electronic Resource
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