Microstructure Evolution of As-Cast Nickel Aluminum Bronze under Electropulsing

Abstract

In this work, the microstructure evolution of as-cast NAB under different electropulsing parameters were studied. The microstructure of the electropulsing treatment (EPT) sample was characterized by mircohardness test and optical microscopy. The results show that compared with heat treatment, when the peak current density reaches 5.84×108A/m2 (no significant change in the structure when the peak current density is lower), the β' phase region undergo phase transition in a shorter time. When the peak current density reaches 7.25×108A/m2, the sample is significantly affected by the Joule heating effect, and the κⅢ and κⅣ phases are successively dissolved to form Widmanstätten α structure. As the β' phase increases and the Widmanstätten α structure forms, the hardness value of the microstructure increases by 80%.