Fig. 1: One-step sustainable synthesis of bulk alloys with defined microstructures from oxides.

a, Schematic comparison between the traditional multi-step alloy-making process and the proposed sustainable ‘one step oxides to bulk alloy’ operation. b, Thermodynamically informed design treasure map. For simplicity, here the reducibility (\(\Delta {G}_{{\rm{oxide}}}-\Delta {G}_{{{\rm{H}}}_{2}{\rm{O}}}\)) is considered for the oxides with the highest valence states at 700 °C under 1 atm. Thermodynamic data for constructing this diagram have been collected from the literature^2,41 and the SGTE database⁴². c, Kinetic conception outlining the two main competing factors in achieving bulk alloys with defined microstructures from oxides, related in part to the present demonstrator Fe–Ni alloy class. The physical rationale of such a proposition lies in the difference between the oxide reduction temperature and the temperature at which complete densification is achieved (typically when T/T_m ≈ 0.75, where T_m is the bulk melting point³⁵; see also Extended Data Fig. 1) in the corresponding metallic phase. The critical heating rate, β_c, indicates the scenario in which complete oxides-to-alloy conversion and complete densification are simultaneously achieved. β₁ and β₂ sketch two heating rates slower than β_c as a guide to the eye.