Fully-annealed Zircaloy-2 tubing was strained by balanced axial stress σ
x and circumferential stress σθ(stress ratio: a=σ
2/σθ). Then, texture and subsequent yield loci of these prestrained materials were measured.
Results of texture measusement after prestraining showed that (0002) poles tend to move towazd the radial tube direction under a=0, 0.5 and 1, but toward the circumferential tube direction under a=2 and ∞. Specimens highly prestrained under a=0 and 0.5 have extremely concentrated texture. Such texture changes can be explained by a deformation model in which <c+a> type slip system was assumed as one of the deformation system. The yield strength of most prestrained materials is higher than that of starting material, however, the material prestrained under a=∞ shows lower yield strength than starting material under test condition of a=0. It was observed that the texture change had an important influence on subsequent yield behavior. Typically, the material highly prestrained under a=0.5, which had concentrated basal poles, gave the yield locus chazacterized by remarkable "texture hardening".
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