Integration of interlayer surface enhancement technologies into metal additive manufacturing:A review

Additive manufacturing(AM)has the advantages of rapid prototyping,high design freedom,and flexible manufacturing,while the mechanical properties of additively manufactured products are not uniform due to inherent defects and residual stresses.Integration of interlayer surface enhancement(SE)technologies into AM is a potential solution to improve the microstructure,close defects,residual stress state,mechanical properties,and chemical properties of formed materials.This paper reviews the current literature on hybrid AM process through the combination of SE and AM,and proves the possibility of integrating SE technologies into AM from the technical level.Then the improvement effects of SE processes on AM parts are introduced in terms of microstructure,defects,residual stress,mechanical properties,and chemical properties.Finally,considering the commonly used directed energy deposition(DED)process and ultrasonic impact treatment(UIT),a closed-loop quality control framework for integration of interlayer UIT into the DED process is proposed.Future research directions to the hybrid AM and interlayer SE are pointed out.