The Effect of Fluid Pressure on the Shear Properties of Metals

Abstract

This paper describes an investigation undertaken to determine whether fluid pressure has any effect on the shear properties of several metals. An apparatus is described in which it is possible to carry out torsion tests under fluid pressure of up to 20 tons per sq. in., and up to 40 tons per sq. in. if another torque bar is used. A simple high-pressure intensifier and secondary pressure gauge are also described. The results show that pressure has no significant effect on the shape of the stress-strain curves of the metals tested, though it does increase the strain-to-failure in some instances. The strain-to-failure appears to increase linearly with pressure, except with zinc and Mazak which give no increase in ductility with pressure. Numerous cracks, which formed in the specimens during test, were found to be inclined to the transverse plane of the specimen and at an angle slightly greater than 45 deg. to the direction of the tensile component of the shear stress.