Effect of the Deformation during Pressure Welding of a Wrought EP975 Nickel Alloy and a Single-Crystal Intermetallic VKNA-25 Alloy on the Structure and Properties of the Welded Joints

Abstract

The influence of the strain (24, 30, 40%) during the pressure welding (PW) of an EP975 alloy in a superplasticity state and subsequent high-temperature heat treatment of welded joints on their structure and room-temperature mechanical properties is studied to find the conditions of PW of a single-crystal [001] Ni₃Al-based VKNA-25 blade alloy and an EP975 disk alloy in order to fabricate a blisk. The tensile strength of the welded samples is found to be maximal after PW of the EP975 alloy at a strain of ~40%, and the strength reached at lower strains is also sufficiently high, 0.7–0.8 of the strength of the VKNA-25 blade alloy. To optimize the technology of solid-phase joining, it is reasonable to decrease the PW strain to 20% and to increase the welding temperature to 1175°C.