Residual Stress Relief in Metallic Materials: Traditional Methods, Emerging Techniques, and Multi-Field Synergies.

Residual stress, an inevitable byproduct of manufacturing processes, significantly compromises the mechanical integrity, formability, and dimensional stability of metallic components. A comprehensive understanding of residual stress evolution and effective mitigation strategies is therefore critical for preventing structural failure. This review systematically examines the generation mechanisms, multi-scale classifications, and performance impacts of residual stresses in metallic structures. We critically evaluate the evolution of stress relief technologies, transitioning from traditional thermal and mechanical methods-which often suffer from high energy consumption, environmental concerns, or geometric distortion-to emerging non-thermal single-field techniques such as ultrasonic, magnetic, and electropulsing treatments. Crucially, this paper highlights a paradigm shift toward multi-field coupling strategies. By synergistically integrating thermal, magnetic, and vibrational energies, novel approaches like Combined Magnetic-Vibration (CMVSR), Thermal-Vibration (TVSR), and Thermal-Magnetic (TMSR) stress relief demonstrate superior stress relaxation efficacy while maintaining microstructural stability and minimizing energy expenditures. Ultimately, this review provides a comprehensive roadmap for selecting appropriate mitigation strategies and outlines the future trajectory of eco-friendly, high-efficiency stress relief in advanced manufacturing.