The High-Temperature Deformation Mechanism in Pure Metals

In order to examine the idea that the high− tenlperature deformation of pure metals is recovery−control工ed， strain rate change tests and stress relaxation tests have been performed using vanadium， alu面nium，copper andα一iron． The work hardening rate without the recovery effect，ん， and the recovery rate，7， are determined at a given deformation state by a stress relaxation test． Slopes of the stress−stram curve immediately after the strain rate change can be calculated froln the values ofんandア． The calculated slopes agree well with the experilnentally determined slopes． The activation energy for recovery determined from stress relaxation tests agrees approximately with the activation energy for self−diffusion． Transmission electron microscopic observations on vanadium suggest that the stress change 4σaccompanying a rapid strain rate change is related to the local variation of the dislocation density． From these results， it is discussed that the high−telnperature deformation of these pure metals can be understood by the recovery−controlled mechanisn1．