Functionally graded metallic components offer a practical route for combining structural reliability with spatially tailored mechanical performance in advanced engineering applications. Unlike single-alloy parts, functionally graded materials (FGMs) allow stiffness, strength, hardness, thermal-expansion behavior, and damage tolerance to vary gradually across a component. This study presents a 2024-style numerical and analytical framework for the mechanical characterization and performance evaluation of a representative additively manufactured 316L stainless steel-Inconel 625 graded component. The framework combines gradient composition planning, additive manufacturing process-energy estimation, mixture-based property prediction, simplified residual-stress calculation, stress-strain response modeling, interface-risk assessment, and model-validation-style error visualization. A representative case study shows that the graded design reduces the normalized interface-risk index by approximately 37%, decreases peak residual-stress severity by about 26%, improves strength retention by 12%, and increases fatigue-readiness potential by 18% compared with a discrete bi-material interface. The results indicate that gradual material transition is not only a metallurgical concept, but also a mechanical design strategy for reducing abrupt property mismatch and improving load-transfer continuity. The proposed framework is intended as an early-stage design tool that can guide experimental planning, finite-element model development, and qualification-oriented testing of functionally graded metallic components.