Achieving High Strength and Good Ductility in a Nb-Containing CoCrNi-Based High-Entropy Alloy by Grain Boundary and Precipitates Strengthening

Face-centered cubic (FCC) high-entropy alloys (HEAs) have attracted considerable attention due to their excellent mechanical properties; however, an insufficient yield strength (YS) limits widespread engineering applications. To improve the of FCC HEAs, present work aims develop fine-grained Nb-containing CoCrNi-based HEAs with precipitates. In work, a single-phase CoCrNi1.5Nb0.2 HEA was processed by cold rolling followed annealing at higher temperature and aging lower temperature, yielding fine- ultra-fine-grained matrices two types precipitates: ultra-fine granular C15 Laves phase CoCrNb-based precipitates lath-shaped D019-structured ε-Ni3Nb-based The resultant alloy exhibits combination high (approximately 1409 MPa strength) good ductility (10.1% uniform elongation). contributions grain boundary precipitation strengthening YS were analyzed calculated. mechanisms underlying discussed.