日本金属学会誌

J. Japan Inst. Metals, Vol. 32, No. 10 (1968),
pp. 943-949

Influence of the Orientation Relationship of Component Crystals on Grain Goundary Sliding of Pure Aluminium Bicrystals

Genjiro Mima1, Toshihiro Oka2 and Koji Baba3

1Department of Metallurgy, Faculty of Engineering, Osaka University, Osaka
2Graduate Student of Metallurgical Engineering, Osaka University, Osaka
3Student of Metallurgy, Faculty of Engineering, Osaka University; now, Nakayama Steel Works Ltd., Osaka

Abstract:

Under tensile load with their boundaries aligned at 45 deg. to the tensile axis of 99.99% aluminium bicrystal specimens, observations were made on the influence of the orientation of component crystals or boundary angle on the grain boundary sliding and shear deformation near the boundary by (1) the creep test, (2) increasing stress with a constant rate, and (3) increasing temperature with a constant rate.
Final grain boundary displacements of three kinds of above-mentioned test, generally, varied linearly with the crystal orientation relationship reported by Rhines et al. However, in the case of the creep test, the deviation from the linear relationship was observed more frequently than in the others.
With increasing boundary shear stress up to 100 g/mm2 with a constant rate of 1 g/mm2/min at 350°C, grain boundary sliding of the specimens was observed at the stress range from 9.5 to 29 g/mm2, with increasing temperature up to 430°C with a constant heating rate of 2.5°C/min under the boundary shear stress of 50 g/mm2, grain boundary sliding of the specimens was observed at the temperature range from 170° to 240°C.
The values of an index of the strength of grain boundary τ0 which was reported previously by us and of the activation energy Q varied as a linear function with the angle ω measured between crystal slip directions on the slip planes of component crystals most paralled to the boundary plane of bicrystal and when the angle ω varied from 14 to 60 deg., the value of τ0 increased from 1.77 × 104 to 3.86 × 104 g/cm2, and the value of Q increased from 10500 to 25000 cal/mol.


(Received 1968/4/16)

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