エッチピット法によるチタン板の結晶粒方位分布の測定

抄録

In this experiment, the procedure to form oriented etch pits on a commercially pure titanium sheet was presented, and the feature of the orientation distribution of grains, containing the orientation relation between neighboring grains, was analyzed by the etch pit method. The shape of the etch pit is coincident with that introduced from the rotation of the 14-hedral model formed by the {0001} planes and the {10\bar11} planes. Shape parameters R_c, R_p and R_a, have the following relation. R_c:R_p=1:1.4 (R_a=R_p⁄sin(61.4π⁄180)=1.6).
Using such oriented etch pits, the feature of the orientation distribution in two differently textured titanium sheets were examined. In the sheets cross rolled at 873 K, 61% of the grains have the c-axis normal to the sheet plane. The preferred orientation is (0001)[10\bar10] and the number of grains with such an orientation are 23.1%. The frequency of the orientation difference of the c-axis between neighboring grains with angles between 0 and π⁄18 is over 80%. In the sheets rolled unidirectionally at 1173 K, the grains with the c-axis parallel to the sheet plane are 50%. The grains with the orientation in the range from (10\bar10)[11\bar25] to (10\bar10)[11\bar2 17] are 12.5% in number. The preffered orientation is from (10\bar10)[11\bar25] to (10\bar10)[11\bar2 17]. The orientation difference of the c-axis between neighboring grains is distributed uniformly in the whole range from 0 to π⁄2, so that this distribution is extremely different from that of the sheets cross rolled at 873 K.