Heat treatment studies of aluminium alloy forgings of the AZ 74.61 type. Interim report no. 3: Fatigue crack propagation performance under manoeuvre spectrum loading

The fatigue crack propagation performance of the alloy AZ 74.61 under manoeuvre spectrum loading was studied. The crack propagation behaviour was also compared with that of the American forging alloy AA 7050, not only for simulated manoeuvre loading but also for simulated gust loading and programme loading. It was found that, at comparable...

The repair of fatigue cracks in low-alloy steel sheet

Fatigue cracks were grown in rectangular specimens with a central notch. At a certain crack length, the crack was repaired, using a variety of methods. Fatigue loading was resumed and re-initiation and subsequent growth of the fatigue crack were studied. The repair methods evaluated comprised simple stopholes, brazed straps across the crack,...