Near‐Defect‐Free Manufacturing and Enhanced Overall Wear and Corrosion Resistances of 316L Stainless Steel Achieved by Interlayer Hybrid Process with Laser Additive Manufacturing, Milling Machining, and Ultrasonic Rolling

To eliminate the internal defects induced by additive manufacturing (AM) process and enhance the metal performances within the entire size, this study proposes an interlayer hybrid process with laser AM, milling subtractive machining, and ultrasonic equivalent rolling. In this study, the interlayer additive/subtractive/equivalent hybrid process is used to improve the overall wear and corrosion resistances of additively manufactured 316L stainless steel (AM316L). The results demonstrate that the interlayer hybrid process has the great potential to achieve the defect‐free manufacturing of metals. The milling subtractive machining plays a crucial role in eliminating large interlayer defects, and the ultrasonic equivalent rolling has significant effects on closing micropores, refining grain size, increasing dislocation density, improving hardness, and enlarging compressive residual stresses in overall AM316L. Benefitting from the near‐defect‐free manufacturing with the porosity value of 0.01% and the interlayer strengthening, the wear and corrosion resistances of AM316L subjected to the interlayer hybrid process are improved with the wear rate and corrosion current density decreased by 8.15% and 43.8%, respectively, and the polarization resistance increased by 37.5%.