The grain refinement mechanisms of various phases in shot-peened Nickel-Aluminum bronze (NAB) alloy

Coarse-grained NAB alloys are subjected to shot-peening (SP) treatment and the grain refinement mechanisms of various phases in shot-peened NAB alloys are investigated separately. The various phases in NAB alloys including α, β and three intermetallic phases (κii, κiii and κiv) display different grain refinement mechanisms. For the α phase, the main grain refinement mechanisms are dislocation segmentation and twinning intersection. For the β phase, the grain refinement is associated with the formation of nano twins. As for κ phases, the strip-shape κiii phases are fragmented after SP treatment while the κiv and κii phases present the twinning and dislocation deformation modes, separately.172