Strain-controlled fatigue of a braze clad Al–Mn–Mg alloy at room temperature and at 75 and 180°C

Strain-controlled fatigue test results at room temperature, 75 and 180°C for a braze clad Al1Mn0.5Mg (wt.%) alloy with the designation 3005LL are presented. The tests have been executed on flat specimens with a 10 mm gauge length. The total strain ranges vary from 0.4 to 1.2%. The frequency is 0.5 Hz and the waveform triangular. The influence of the cladding on the fatigue properties is strain range dependent. The fatigue life for clad specimens is shorter than that for the unclad core material at higher strain ranges while the life difference is small at lower strain ranges. The results show that cracks during fatigue propagate through the brittle eutectic zones in the cladding layer and into the core, thereby degrading the fatigue life. The test temperature influences the fatigue properties of 3005LL. When the combination of stress and strain (half-life hysteresis energy) is considered as the controlling parameter for the strain-controlled fatigue of 3005LL, however, the fatigue properties are similar at different test temperatures.