Apparatus for studying cyclic stress-strain and fatigue at elevated temperatures

An apparatus is described which permits tubular specimens to be heated to a uniform temperature, while being cyclically strained with a constant amplitude of alternating strain about a fixed mean strain. Under these conditions, tests were performed in which the mean stress was measured as a function of the number of cycles of repeated strain for the alloys Udimet 700 and Rene 41 at 1300°F. These data along with fatigue fracture data are reported.