The development, analysis, and optimization of both advanced and additively manufactured materials and components require a deep understanding of their mechanical behavior, especially as influenced by microstructural features. Advanced manufacturing techniques, including additive manufacturing (AM), introduce unique challenges—such as high thermal gradients and process-specific defects—that may significantly affect material performance. This symposium will explore the intricate interplay between microstructure, defects, and mechanical properties across a range of materials including metals, polymers, ceramics, and composites. Emphasis is placed on understanding failure mechanisms under combined physics loadings, where mechanical stresses interact with thermal, environmental, or other physical forces to influence fracture behavior.