JOINING OF ADVANCED STRUCTURAL MATERIALS BY PLASTIC DEFORMATION

摘要

Superplastic deformation has been employed to join nickel aluminide (Ni_3Al) at temperatures of 1000-1200°C and strain rates ranging from 1 × 10~(-3)/s to 5 × 10~(-3)/s. Optimum joining was achieved at 1100°C for strain rates ranging from 1 × 10~(-4)/s to 9 x 10~(-4)/s. Corresponding flow stresses were 47-123 MPa with permanent strains≈10%. The room-temperature stress-strain of the joined flexure bars made at 1100°C was similar to that of monolithic samples. The role of surface oxidation conducted at 1100-1200°C on the joint quality was also investigated.