日本金属学会誌

J. Japan Inst. Metals, Vol. 63, No. 3 (1999),
pp. 326-332

Influence of Plastic Anisotropy on High Temperature Strength ofSingle Crystals of a Nickel-Base Superalloy

Koji Kakehi

Department of Mechanical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji 192-0397

Abstract:

The effects of crystallographic orientation on the tensile and creep strength of the notched specimens of single crystals of a nickel-base superalloy have been examined at 900°C. The different plastic anisotropy among four kinds of the notched specimens was interrupted by changing the arrangement of slip systems. The tensile and creep strength of the notched specimens were affected by the crystallographic orientations not only in the tensile direction but also in the thickness direction. At 700°C, assuming that {111}<{101}> type slip systems were operated in the tensile tests and the {111}<{112}> type slip systems in the creep tests, the test results could be explained very well. In this study, at 900°C, the results of the tensile tests and creep tests were discussed on the assumption of that {111}<{101}> type slip (octahedral slip) systems were in operation. The test results could not be explained just by the operation of the {111}<{101}> slip system. Therefore, it was assumed that the operation of {010}<{101}> type slip (cube slip) systems and diffusion-controlled deformation mechanisms should be taken into account at this temperature.


(Received May 27, 1998; In Final Form September 2, 1998)

Keywords:

single crystals, crystallographic orientation, a nickel-base superalloy, plastic anisotropy, tensile strength, creep strength, arrangement of slip systems


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