The Influence of Composition, Temperature and Strain Rate on the Deformation of F.C.C. Metals and Alloys

Abstract

Various methods of assessing deformation behaviour are considered and compared, and torsion is selected as a convenient means of obtaining data to high strains, over a range of temperatures and strain rates. Parameters which describe the most relevant features of torsion test results are suggested. The way in which the descriptive parameters are effected by changes in composition, grain size and conditions of testing are investigated by multiple regression analysis for a number of pure metals and single phase f.c.c. alloys. A series of equations are produced which are applicable over the whole range of compositions considered. Based on the equations derived it is suggested the most important factors relating to composition are shear modulus, Burger’s vector and stacking fault energy. Structure may be described by the reciprocal square root of grain size, and of the process variables temperature is shown to be much more influential than strain rate within the range of values used. Comparison of the regression equations shows that the process termed restoration, by which the strains induced by work-hardening are relieved, is predominantly recovery by Dislocation climb rather than recrystallisation involving grain boundary migration.