5056アルミニウム合金平滑材における疲労き裂発生と疲労き裂伝ぱ特性

概要

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Fatigue properties of 5056 aluminum alloy, which is the most Mg-rich alloy among commercial Al-Mg alloys, and exhibits significant work hardening and strain aging, was investigated. Rotation-Bending tests with smooth specimen were performed at room temperature, with stress ratio R-1 and frequency of stress cycle f=55Hz. The experimental results showed that a clear fatigue limit like in case of a steel existed on the S-N curve. Surface observation with the replica method revealed a wavy pattern around the second phase particle for N10^6-10^7, but no non-propagation crack were observed. It was speculated that the observed fatigue limit appeared as a result of marked work hardening and strain aging at the heavily deformed zone, and fatigue cracks did not initiate from the zone at up to the maximum number of stress cycle, N=3.5×10^7, employed in the present study.
2010-07-25