High tensile ductility and strength in a gradient structured Zr

Abstract We report that a gradient structured Zr processed by asymmetric rolling and partial annealing possesses an exceptional synergy of high strength (σy ∼ 550 MPa) and high tensile ductility (eu ∼ 10.1%) much better than that (σy ∼ 250 MPa and eu ∼ 14.2%) of its coarse-grained (CG) counterpart. This gradient structure is characterized by a gradient dislocation density distribution from the surface to the core and composed of microscale and ultra-fined elongated grains connected by low angle grain boundaries (LAGBs). These findings can provide valuable insight for designing gradient structures with excellent mechanical properties.