Accommodation Mechanisms and Dispersoid-Free Zone S in al 7475 after SuperplasticForming

摘要

Investigations which supplement accommodation models additional to grain boundarysliding for the alloy Al 7475, which are necessary to maintain material compatibility, are described. The experiments carried out under superplastic deformation conditions were performed on uniaxial tensile specimens as well as on experimental parts with a biaxial stress mode. The microstructure, the cavitation behavior, the strain, and the strain rate conditions were investigated on these specimens. During the superplastic forming process on Al 7475, large dispersoid free zones are generated. The interdependence between dispersoid free zone, accommodation process, cavitation behavior, strain, and strain rate are discussed. If these zones are regarded as markers for accommodation processes, grain boundary migration is the main accommodation mechanism of this alloy.