High Temperature Fatigue; Dwell Sensitivity and Life Prediction

摘要

The objectives of this research were to develop knowledge to address dwell211u001esensitivity behavior of high temperature materials and to predict dwell 211u001esensitivity and creep-fatigue life. The damage mechanisms resulting from various 211u001edwell cycles were summarized for a range of materials that operate at high 211u001etemperatures. An attempt was made to predict dwell sensitivity based on the 211u001etensile properties correlating strength ratios at room and high temperatures. A 211u001erelationship exists between these two strength ratios, which was exploited to 211u001epredict the dwell sensitivity behavior of materials. Also, a conceptual model was 211u001edeveloped to predict dwell sensitivity utilizing cyclic hardening and softening 211u001ebehaviors of materials in two directions, namely tension and compression. 211u001eAnalytical models were developed to predict the dwell fatigue life, in which 211u001ecreep and fatigue interact.