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.