Original paper(Vol.46 No.7 pp.756)

X-ray stress measurement on Ni₃Al specimens by using imaging plate

Sasaki Toshihiko; Goto Tokimasa; Tabata Hiroyuki; Hirose Yukio

Abstract:The X-ray stress analysis was examined for an arc melted Ni₃Al intermetallic compound, which consists of coarse grains and exhibits strongly preferred orientation. The imaging plate was used as an X-ray detector, and continuous Debye Scherrer rings were obtained from such coarse grained material by applying an X Y plane oscillation method. Mechanical bending stress was applied to the specimen for measuring the X-ray elastic constants and stress constant. An ideal orientation method was adopted to obtain these parameters. It uses the diffraction lines which belong to the same zone axis. These experimental elastic constants were compared with the theoretical values calculated from the elastic compliance of Ni₃Al single crystal.
The results obtained are summarized as follows;
(1) The X-ray elastic constants measured from Ni₃Al 220 diffractions which appeared at psi = 0.537 degree and 60.537 degree , were E_X/(1-u_x) = 176 GPa, E_X = 220 GPa and u_x = 0.5. (2) The theoretical Young's modulus E₀ at y = 0 degree was calculated as 207 GPa from the elastic compliance of Ni₃Al single crystal. This value means the elastic constant in the direction of the tensile axis for the grains which contribute to the diffraction. Young's modulus E₆₀ at y = 60 degree was similarly obtained as 228 GPa. The experimental value of X-ray elastic constant E_X (220 GPa) was intermediate between the theoretical values.

Key Words:X-ray stress measurement, Ni3Al intermetallic compound, preferred orientation, coarse grain, imaging plate, X-Y plane oscillation method, X-ray elastic constant