The stress coupling mechanism of laser additive and milling subtractive for FeCr alloy made by additive –subtractive composite manufacturing

Abstract

Additive manufacturing is a revolutionary frontier technology in the manufacturing industry. High-performance metal materials made by laser additive manufacturing are usually required subtractive machining to meet the assembly accuracy requirements. The stress coupling mechanism of FeCr alloy made by laser additive and milling subtractive is worthy of being studied. In present work, the impact of milling on residual stress of laser additive layer was investigated through experiments. The coupling interaction mechanism of laser additive stress and milling subtractive stress was analyzed. The key findings of this study are: (a) milling can change the near surface residual stress distribution of FeCr alloy made by laser additive manufacturing, resulting in a certain depth of compressive stress affected zone; (b) Mechanical load generated by milling is the main cause of compressive stress near the surface; and (c) the magnitude of compressive stress is affected by the combined effects of mechanical load and thermal load introduced by milling.