Multiscale computational and experimental insights into thermal history and composition based study of strength-ductility synergy in Zr-enhanced AlSiMg alloys

X Wang and YX Geng and Y Oliinyk and ZJ Zhang and A Kunwar, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 944, 148865 (2025).

DOI: 10.1016/j.msea.2025.148865

Zr-enhanced AlSiMg1.4Zr alloy fabricated via selective laser melting (Pi = 250 & 350 W, vs Qa = 800-1200 mm/s) exhibited a distinctive cellular substructure, accompanied by the formation of Si nanoparticles within the a-Al matrix upon direct aging treatment (150 degrees C-24 h). The non-uniform thermal history caused the hierarchical formation of high- density stacking faults at nanoscale and a bimodal structure at microscale, leading to a substantial improvement in the alloy's strength while maintaining high ductility. Effects of nonuniform thermal field in the multiscale mechanical behavior of the structure has been assessed numerically by incorporating the temperature dependence of Hollomon parameters in finite element analysis and stacking fault energy (SFE) in molecular dynamics (MD) simulations. Through a materials informatics approach, it has been quantified that the Pearson correlation coefficient between SFE and temperature attributes in generic alloys is merely 0.051, underscoring the need for a physically grounded mechanical model-such as MD simulations, to rigorously capture the thermal effects on stacking fault behavior. Thus, a novel alloy design and fabrication approach has been presented in this work for overcoming the strength- ductility trade-off of aluminum alloys. This tailored design and manufacturing method ensured the ductility of AlSiMg1.4Zr alloy to 13.0% while achieving a yield strength of at least 350.0 MPa, whereas for a yield strength exceeding 425.0 MPa, it produces samples with a maximum ductility of 10.0%.

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