Hierarchical Chemical Ordering Enables Ultra‐Efficient Strengthening and Multifunctionality

Modern alloy design increasingly seeks substantial strengthening with minimal alloying to improve sustainability while preserving or enhancing matrix functionality, an imperative for high-end applications like biodegradable implants. Yet for over half a century, strengthening has relied on introducing intensive defects via heavy alloying to impede dislocations; unfortunately, those defects inevitably induce functional degradation, producing a persistent strength-functionality trade-off. Here, we transform grain boundary (GB) sliding, typically a source of softening, into an ultra-efficient strengthening mechanism via engineered hierarchical chemical ordering (HCO). In a model biodegradable near-pure Zn alloy with only 0.17 at.% solute (Zn-0.12Mg-0.05Mn), yield strength increases tenfold to 350 MPa and represents the largest gain for ultra-lean alloys below 0.5 at.% while exceeding clinical benchmarks. The alloy delivers 32% elongation and uniform biodegradation that exceeds even what was long considered exclusive to pure metals, with 10%-37% higher cell viability, 38% enhanced wound healing, and uncompromised electrical conductivity. The HCO achieves dual-range strengthening as intragranular Mn-rich nanoclusters elevate GB motion stress by ∼164% through long-range suppression of stress relaxation, while Mg segregation at GBs increases critical sliding stress by ∼600% via short-range pinning. This mechanism bypasses traditional strength-functionality trade-offs, establishing a new design paradigm for ultra-lean, high-performance alloys.