抄録
A cyclic stress measurement method that focuses on the density and the preferred orientation of grown grains was investigated using an electrodeposited nickel foil. The nickel foil was adhered to the titanium alloy specimen and the cyclic loading test under various biaxial stress conditions was carried out. The ambient temperature during the test was set to 175 － 250℃. Then the grown grain density was measured and the crystallographic orientations were also analyzed by electron backscatter diffraction. Since surface state of the substrate on which mirror finishing had been performed was transferred to the initial electrodeposited surface, grown grains can be observed by the microscope without electrochemical polishing and etching. The relationship among grain growth density, maximum shearing stress, number of cycles and ambient temperature was formulated on the basis of the experimental results. In addition, due to the difference in the original orientation between nickel and copper foils, preferred orientation of grown grains was also different in both foils. However, the slip direction of grains agreed well with the maximum shearing stress direction in both foils. On the basis of this feature, principal stresses can also be determined using the pole figure of grown grains.
