A census of superplasticity in aluminum and magnesium alloys: process-window topologies, quantitative benchmarks, and design rules under dual-gate constraints

초록

Superplasticity in aluminum (Al) and magnesium (Mg) alloys has been studied for decades, yet a unified quantitative account of where superplasticity is achieved in strain-rate (ε̇)–temperature (T) space and which metallurgical constraints control process-window robustness remains lacking. Here, we compile a 40-year literature census into unified ε̇–T maps using a common qualification criterion of elongation-to-failure Ef ≥ 300%, quantify window breadth and edge reach toward low-temperature superplasticity (LTS) and high-strain-rate superplasticity (HSRS), and assess window continuity and fragmentation from the mapped distributions. At the census level, Al alloys show very limited LTS but can develop broad HSRS-capable domains once thermally activated, whereas Mg alloys access LTS more frequently but generally require higher temperatures for HSRS. Five recurring process-window phenotypes, Types I–V, are identified and interpreted using a dual-gate framework. Gate A describes accessibility into the grain-boundary-sliding-compatible branch through threshold-stress and accommodation constraints, whereas Gate B describes retention of the fine-grained boundary network against forming-time coarsening. Metallurgical anchors—the solidus-onset temperature (Ts) and effective solvus temperature (Tsolvus,eff)—link phase stability to threshold-stress relief and grain-boundary retention. A minimal two-branch model coupling grain boundary sliding, dislocation-controlled deformation, and grain-growth-mediated retention reproduces the major phenotype geometries, converting scattered reports into a diagnostic atlas for process-window design. © 2026 Elsevier Ltd

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