Plastic Strain Fatigue in Air and Vacuum

Abstract

The plastic strain-life relation for several ductile materials is examined in both air and vacuum and interpreted in light of the well-known plastic strain (ΔξP ) life (N) relation, N1/2 ΔξP = constant. These data indicate that the relation applies as well in vacuum as in air and, in certain cases, better and to a much larger number of cycles. Further experiments are described in which these materials are repeatedly fractured and rejoined in vacuum, exhibiting a very substantial capacity for vacuum cold reweldment of completely fractured specimens.