Temperature Effects on the Fatigue Behaviour of an Aluminium-Silicon Aloy

Abstract

The fatigue behaviour of BS1490 LM-30 aluminium-silicon alloy has been investigated at room temperature and at a comparatively high temperature of 250°C. ASTM type compact specimens have been used to gather information about the fatigue crack growth behaviour in this cast aluminium alloy at 250°C and a comparison made with the results of simitar tests at 20°C. The effect of stress ratio was investigated and fatigue crack growth thresholds were established for the stress ratios R=0.08, 0.5 and -1.0. The overall appearance of all the fractured surfaces was brittle and fractographic observations showed that the silicon precipitate determines the mode of fracture in the investigated temperature range.