A quick-quench technique for the study of creep cavitation in metals

Abstract

A quick-quench technique has been developed for the study of creep cavitation in metals and alloys. With such a technique, the specimen could be quenched from the test temperature to 50°C within 5 minutes. Couple with standard metallographic techniques, the above quick-quench technique has been successfully applied to investigate the evolution of creep cavities in pure and OFHC copper, especially during the early stage of creep deformation. The result shows that a threshold strain of about 0.1 to 0.5% is required for cavitation in pure copper, while it is negligible for cavitation at inclusion sites at grain boundaries in OFHC copper. It also shows that for metals and alloys containing low to moderate amounts of inclusions or second-phase particles, although the second-phase particles provide easy cavitation sites at grain boundaries during the initial stage of creep deformation, the creep cavitation behaviour at large strains is controlled by cavitation at 'normal' sites at grain boundaries. Works in the literature show that such 'normal' sites are probably the intersections of subboundaries at grain boundaries [12,14-16].