Exceptional creep resistance enabled by thermally stable cellular dislocation structures in an additively manufactured multicomponent alloy

Abstract

An additively manufactured (AM) FeNiCoCr-based multicomponent alloy (MCA) with prominent cellular dislocation structures was produced using the laser powder-bed fusion (LPBF) method. Creep tests were conducted on the alloy at a high temperature of 650 °C by a tensile stress of ∼100 MPa for more than 100 h, and a significantly low creep strain of less than ∼0.023 was attained at the end of the test. It is found that the cellular dislocation structures exhibit high thermal stability and stabilize the dislocation networks at elevated temperatures, inducing considerable obstructions against plastic flows and accordingly inhibiting the dislocation-mediated creep deformation. Combined with the instinct of sluggish diffusion effects of MCAs, the LPBF-printed alloy possesses exceptional creep resistance compared with its counterparts produced via conventional casting methods. This work provides a new strategy for developing advanced structural materials for high-temperature service environments, through rationally designing thermally stable cell structures of AM-produced alloys.