CYCLIC LOADING EFFECTS ON THE CREEP PROPERTIES OF SHEET MATERIALS

摘要

An investigation was made to determine the effects of cyclic loading on the high temperature creep deformation rate of metals, particularly as related to conditions encountered in jet propul?sion engines. Armco iron and commercial high purity aluminum were used to establish generalizations concerning the following vari?ables: (a) amplitude of cyclic load between 0 and 50％ of the mean stress, (b) temperature (cold working and annealing ranges), and (c) frequency of load variation from 1.5 to 4,200 cycles per minute.nThe data show that the superposition of a cyclic load upon a static tensile load in a creep test on Armco iron will not necessarily cause deformation to proceed at an increased rate provided the frequency is high enough for the conditions of stress and temperature which prevail. Only a limited amount of data was obtained for the aluminum prior to termination of the project.