|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Ultrafine-grained and Heterostructured Materials (UFGH XII)
||Dual-gradient structure leads to optimized combination of strength-ductility synergy and high fracture resistance suppressing catastrophic failure
||Qin Yu, Ruqing Cao, Yi Li, Robert O Ritchie
|On-Site Speaker (Planned)
Nature-inspired gradient structures have been engineered to achieve strength-ductility synergy; however, the fracture properties of gradient structures remain relatively unexplored. By fabricating centimeter-sized nickel samples using direct current electroplating techniques, we demonstrate that a dual-gradient architecture containing grain-size gradients transitioning from coarse grains to nano grains, and to coarse grains again, i.e., CG→NG→CG, can achieve an optimized combination of strength-ductility synergy and superior fracture resistance with stable rising R-curve having an initiation toughness exceeding 300 MPa.m½. Significantly, the brittle crack propagation in the central nano-grained zone can be effectively arrested in the later coarse-grained zone, contributing to an even higher crack-growth toughness exceeding 350 MPa.m½. We believe the dual-gradient CG→NG→CG structure represents an optimized prototype architecture for designing multi-layer graded structures with exceptional combinations of mechanical properties.