Modular Combinatorial Development of Crystal‐Glass Nano‐Heterostructured Copper Alloys with Ultrahigh Strength and Large Deformability

Abstract Overcoming the strength‐ductility trade‐off in metals and alloys entails the optimization of the compositions and dedicated microstructural design, which remains experimentally laborious and challenging. Here, a combinatorial method is devised to construct a Cu‐Ti alloy library encompassing diverse compositions, microstructures, and mechanical properties, allowing to efficiently identify a copper alloy with an unprecedented yield strength of 3.8 GPa and high deformability. The exceptional properties are attributed to a crystal‐glass nano‐heterostructure (CGNH) consisting of nanograins, nano twins, and glassy phases. Ultrahigh strength stems from the extreme strengthening of structural‐unit refinement and the avoidance of softening caused by grain‐boundary sliding through the inclusion of glassy phases between nanograins. Remarkable deformability is associated with the activation of homogeneous flow in nanosized glassy phases, complemented by coordinated nanocrystal rotation. The CGNH architecture offers a potent route to overcome the trade‐off between alloy strength and deformability.