A novel method for investigating microstructure-property relationships by integrating digital microstructure mapping and FEM: a case study of Cu–Ni–Al alloy

This work proposes a novel framework integrating digital microstructure mapping with FEM to investigate microstructure-mechanical property correlations in precipitation-strengthened Cu-Ni-Al alloys. Focusing on Cu-15Ni-4Al, a high-fidelity digital twin of the real precipitate network was constructed through high-resolution characterization, AI-driven segmentation, and quasi-3D FEM modeling. Results indicate aging temperature significantly regulates L1 2 -Ni 3 Al precipitates: aging at 773 K yields dense nanoscale continuous precipitates (CP), achieving an excellent combination of strength (740 MPa) and ductility (∼13%); whereas aging at 973 K leads to coarse discontinuous precipitates (DP) along grain boundaries, causing sharp declines to 570 MPa and ∼6%. FEM simulations based on real microstructures accurately reproduce tensile fracture behavior, revealing distinct failure mechanisms: cracks in CP regions initiate within the matrix and propagate along high-strain bands, while DP cracks preferentially nucleate at coarse precipitate/matrix interfaces and propagate rapidly along them. Experimental fractography aligns closely with simulations, validating this digital mapping approach’s reliability. Furthermore, DP/CP mixed regions suffer simultaneous degradation of both strength and ductility due to accelerated stress transfer effects, highlighting mechanical antagonism induced by microstructural heterogeneity. This work establishes a physics-driven, generalizable multi-scale design platform, providing a new paradigm for the rational design of high-performance copper-based alloys.