부산대학교 도서관

The paper explores fatigue at both low and high temperature where creep and environmental damage interact with the normal cyclic processes of crack development. This is achieved by studying two contrasting material systems: the titanium alloys (Ti685, Ti834, Ti6246) and the nickel alloys (Udimet 720Li). Particular attention is given to both load and strain control fatigue response and crack development at stress concentration features. In each case there is an interesting balance between the beneficial effects of stress relaxation and the damaging effects of creep and environmental factors. On the crack growth side, the relative contributions of creep and environment are highlighted through measurements made in air and vacuum and by varying R value and dwell time. At the same time, any complications due to closure are removed by careful measurement of closure levels for each condition. The inadequacy of linear damage models for combining cyclic and time dependent effects is highlighted. [ABSTRACT FROM AUTHOR]