Mechanisms for Goss-grains induced crack deflection and enhanced fatigue crack propagation resistance in fatigue stage II of an AA2524 alloy

The fatigue behavior of three different AA2524 alloy sheets respectively with dominant Goss+Cube-grains, Cube-grains and Cube+Brass-grains was characterized in present work. Results showed Goss+Cube-grain sheet possessed a much lower fatigue crack propagation (FCP) rate than Cube-grain sheet and Cube+Brass sheet. The Cube+Brass sheet had the greatest fatigue crack propagation rate among the three kinds of commercial sheet in spite of the grain size smaller than Cube-grain sheet. EBSD detection results indicated Goss-grains had a twist component boundary or great tilt angle component boundary with the neighboring grains, thereby retarding fatigue crack propagation in fatigue Stage II more effectively. Apparently, the high intense Goss-grains were responsible for the enhanced fatigue crack propagation resistance of AA2524 alloy.