時効硬化Al合金6061-T6の微小き裂伝ぱ速度の統計的検討

抄録

In order to clarify the statistical characteristics of scatter in the crack growth rate of an age-hardened Al alloy 6061-T6, rotating bending fatigue tests of smooth specimens were carried out at several stress levels. Fifteen or seventeen specimens were fatigued at each stress level and the initiation and propagation behaviors of major cracks were examined for all the specimens. The crack growth rates were calculated based on the smoothed growth curves. The crack lengths at which the growth rates were calculated were 0.03, 0.1, 0.5, 1 and 3mm. The statistical treatments of each set of growth rate data were performed by assuming the Weibull distribution. The scatter characteristics of these growth rate distributions were investigated based on the CV vs σ_a relation (CV : coefficient of variation, (σ_a : stress amplitude).