Core Insights - Metal fatigue is referred to as the "invisible killer" of engineering materials, posing potential threats to the safety and reliability of major engineering projects in fields such as aerospace, energy equipment, and transportation [1][5] - Chinese scientists have published a viewpoint article in the journal Nature Materials, emphasizing the need to break through current research bottlenecks in metal fatigue by advancing both fundamental research and engineering applications [1][4] Summary by Categories Fundamental Research - The article highlights the importance of exploring the fundamental fatigue characteristics of new materials, such as cross-scale multi-level structured metals, to reveal their evolution laws and physical essence [4] - A deeper understanding of the microscopic mechanisms of metal fatigue damage is essential for advancing the field [4] Engineering Applications - The focus is on studying the fatigue damage behavior of traditional metals and related components under complex service environments, particularly under asymmetric or multi-axial complex fatigue loads and extreme conditions (e.g., high temperature, low temperature, irradiation, corrosion, and their interactions) [4][5] - The article stresses the need for innovative integration of material design, advanced manufacturing technologies (such as additive manufacturing), high-precision characterization methods, and AI-assisted analysis to address these challenges [4] Challenges and Future Directions - Despite nearly two centuries of research on metal fatigue, it remains one of the most challenging topics in materials science, especially in extreme environments like deep space exploration and nuclear energy systems [5] - The rapid development of new material systems and the expansion of engineering application scenarios present new challenges to traditional fatigue design methods [5]