| The steady state creep behavior of Pb-In solid solutions was studied over a composition range of 20 to 50 weight percent In. Constant stress creep tests were performed in the stress range 0.37 to 28.96 MPa and in the temperature range 43 to 216(DEGREES)C. Stress exponent and activation energy measurements indicate a transition of controlling mechanism from volume diffusion controlled glide at low stresses to core diffusion controlled glide at high stresses. The relationship between the activation energy for steady state creep and diffusion will be examined. In addition, it was discovered that Pb40In alloys with grain size less than 0.08 mm exhibit superplastic behavior. This indicates that two phases and small grain sizes are not necessary requirements for a material to exhibit superplastic behavior. Finally, a theory will be presented to show that internal back stresses should be proportional to the applied stress during steady state creep of "glide controlled" alloys. |
