The Effect of Compressive Stresses on the Linear Thermal Expansion of Magnesium and Steel

Abstract

A series of cylinders of annealed, extruded, pure magnesium and medium soft steel were subjected to a sequence of compressive stresses at room temperature and their respective coefficients of linear thermal expansion in the direction of stress application were determined for the range 20° to 100°C. The cylinders were then heat treated to permit either recovery or recrystallization and the changes in length were measured. Characteristic curves are given for each metal in which the coefficient of linear thermal expansion and length changes are plotted as a function of the true compressive stress. It is shown that these properties may be used to determine the stress history of a test specimen for which characteristic curves are available. It is suggested that this stress analysis technique may find application in the study of rock deformation and in the investigation of metals, both before and after failure.