ISSN:
1460-2695
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract— The progressive change of mean strain during the cyclic plastic deformation of a material between fixed stress limits is commonly called cyclic creep. If, in tension-compression testing, the mean stress exceeds a certain critical small compressive value, shortening is to be expected; but, if it is less than this or if it is tensile, lengthening is to be expected. The value of the mean stress decides the eventual direction of cyclic creep but not necessarily the initial direction of cyclic creep. In a pre-strained metal, the form of the tension and compression curves differs because of the Bauschinger effect. This affects the behaviour of the material during the first cycle and also, to a decreasing extent, during subsequent cycles. Thus, if the mean stress tends to cause cyclic creep in a direction opposed to that in which pre-straining has induced initial creep, a reversal of creep can occur. Observations have been made of the phenomena in mild steel (for both directions of pre-strain) and also in high conductivity copper.It was found that the phenomenon of creep reversal does not depend on the metal undergoing cyclic hardening or softening. However, changes in the strain range and changes in the mean strain caused by cyclic creep itself produced changes in the limits of true stress when cycling was carried out between fixed limits of nominal stress. It was also shown that a reversal of cyclic creep might occur as a result of cyclic hardening or softening of a metal which possesses similar tension and compression characteristics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1460-2695.1979.tb00386.x
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