Study on ageing and creep of Al–0.1Zr alloy

The influence of ageing process on speed of the creep crack growth of aluminum alloy containing 0.1% zirconium has been studied. By TEM and EPMA, the effect of ageing precipitates’ size and distribution on the creep crack growth of the alloy has been also analysed. The results show that many Al3Zr particles can be precipitated out from the matrix after aged at 250 °C for 48 h. The particles are fine and dispersive, and lay in grain or on grain boundary. These particles can prevent the creep crack growth effectively. In this case, a small amount of zirconium exhibits stronger ability to resist creep crack growth. After aged at 200 °C for 48 h or aged at 250 °C for 24 h, the precipitated particles are invisible and cannot restrain the creep crack forming and growth effectively. After aged at 300 °C for 48 h, the alloy is overaged. The peak of age hardening curve corresponds to the ageing process of 250 °C × 48 h after a 530 °C × 1.5 h solution treatment.