Papers by Keyword: Single Crystal

Abstract: Room temperature fatigue crack growth behaviour of un-exposed(as-received) and high temperature air-exposed(at 1100°C for 24 to 1000 h) CMSX-10 was investigated. A small compact tension specimen with [001] loading direction and [110] fatigue crack growth direction was used. The fatigue crack growth results were analyzed using a stress intensity parameter K . It is shown that the air-exposure has no deteriorative effect on the crack growth behaviour, even though the microstructure has changed by the exposure(coarsening of γ' ). The crystallographic facet fracture of (1-11) and (-111) planes appeared and the intersection of the planes forms sets of lines(ridge and valley) parallel to [110] direction. The fatigue crack tip front is schematically shown.

Abstract: [MnO2(1.0mol%) : Tb4O7(0.5mo%)] doped stoichiometric LiNbO3 (Mn:Tb:SLN) single crystals of 0.5~1.0 mm in diameter and 30~35 mm in length were grown by micro pulling down(µ-PD) method. We investigated the photoluminescence (PL) properties of Mn:Tb:SLN single crystal. The OH- absorption band of the single crystals observed infrared the absorption spectra by using an FT-IR spectrophotometer at room temperature. Homogeneous distributions of Mn and Tb concentration were confirmed by the EPMA and observed defects by optical microscopy.

Abstract: Orientation rotation behaviors taking place in aluminum single crystal and polycrystal were studied during uniaxial tensile deformation at room temperature. Specimens were elongated in an in-situ deformation stage equipped on a high resolution electron backscattered diffraction (HREBSD)system. A series of crystallographic evolution and deformation behavior of concerned areas in the specimens during deformation was directly analyzed using HR-EBSD.

Abstract: Single crystals of AlMgB ₁₄ and AlMgB ₂₂ were grown from a high-temperature aluminum metal flux in an Ar atmosphere. The optimum conditions for growing AlMgB ₂₂ and AlMgB ₁₄ were established using the starting mixtures of B/Mg=0.5-1.0 and B/Mg=2.0-6.0. The AlMgB ₁₄ and AlMgB ₂₂ crystals obtained have well-developed {001} and {100} faces, and were black with a metallic luster. The maximum dimensions of these crystals were about 5.2 mm and 4.6 mm, respectively. The values of micro-Vickers hardness of the AlMgB ₁₄ and AlMgB ₂₂ crystals are in the ranges of 23.9±0.6-27.6±0.6 GPa. The oxidation process of AlMgB ₁₄ and AlMgB ₂₂ crystals were studied up to 1473 K by TG-DTA method. The susceptibility of AlMgB14 with an increase at low temperatures does not show any particular features, being indicative of a paramagnetic contribution, which is likely due to impurities. The susceptibility of the AlMgB ₂₂ sample shows no apparent contribution from impurities and also does not have any anomalous behavior.