Abrasive fluidized bed finishing of additive manufactured cobalt-chrome parts: effects on surface morphology and fatigue behavior

Abstract

The possibility of processing cobalt-chrome parts by additive manufacturing opens the way to the production of complex net-shaped parts able to withstand high loads and at the same time resist the corrosive environment or thermal loads. However, the surface morphology typical of additive manufactured parts could be detrimental to the fatigue life, and finishing operations become necessary. In this paper, the adoption of abrasive fluidized bed (AFB) processing as a finishing solution is explored, and the effect of the main process parameters, namely the abrasive type, treatment time, and rotational speed, on morphological features and fatigue life is investigated. Field emission gun-scanning electron microscopy and contact gauge profilometry showed an improvement in sample finishing due to the AFB process. The advantages in surface properties were related to an increase in fatigue life. The experimental results show that AFB has a beneficial effect both on the finishing and fatigue behavior of additively manufactured components; a smoother surface was obtained, and the crack initiation during fatigue tests was retarded.