Extended Data Fig. 9: Validity of the proposed design treasure map.

a, TGA analysis of the synthesis process. Following the exact synthesis route described in the main text, we start with green compacted pellet of Fe₂O₃, NiO, and Co₃O₄ powders aiming for the super invar alloy composition⁴⁰, Fe₆₃Ni₃₂Co₅ at. %. Following the kinetic guideline discussed in main text Fig. 4 we adopted a consistently slow heating rate of 5 °C/min, followed by 1 hr holding at 700 °C, and 30 min pressure free sintering at 900 °C. b, Bulk thermal expansion response of the synthesized alloy measured by dilatometer. A noticeable near zero coefficient of thermal expansion (CTE) region is present, which well aligns with the literature data⁶² of the same alloy fabricated through conventional melting and casting routes. c, The synthesis alloy exhibits a fine-grain fully densified microstructure with an average grain size of ~1.20 μm (excluding the Σ3 annealing twin boundaries). d, Phase map showing the single FCC-phase constitution of the alloy where BCC or residual FeO_x phase is not detected. e, EDS maps confirming the grain-level uniform distribution of the alloying elements Fe, Ni, and Co and their contents aligns with the conceived values for a Fe₆₃Ni₃₂Co₅ super invar alloy.