Fatigue properties of ARB-processed Ti sheets with crystallographic texture

• Fatigue properties in UFG Ti fabricated by ARB were investigated.
• Fatigue limit significantly increased after ARB.
• Fatigue crack initiation life depends on ease of the prismatic slip.

Dependence of grain morphology and crystallographic texture on fatigue properties in commercially pure Ti sheets processed by 6 cycles of accumulative roll-bonding (ARB) were investigated. The 6-cycle specimens consisted of fine equiaxed and elongated grains parallel to the rolling direction (RD) and had a basal texture with a c-axis inclined 24° from the normal direction toward the transverse direction (TD) of the sheet. Constant stress amplitude testing and fatigue crack growth testing were carried out to evaluate fatigue properties of the 6-cycle specimens. Both fatigue tests were carried out at a frequency of 10 Hz at room temperature. Stress ratios were R = −1 for constant stress amplitude testing and R = 0.1 for fatigue crack growth testing. Two loading directions were used in each fatigue test. Crystallographic texture strongly affected fatigue crack initiation life, which was greatly delayed in TD loading compared with RD loading. Conversely, fatigue crack propagation behavior did not depend on sheet direction due to mutual cancelation effects of the grain morphology and crystallographic texture.