Achieving ultrahigh strength and ductility in biodegradable Zn-xCu alloys via hot-rolling and tailoring Cu concentration

In this present paper, a biodegradable Zn-xCu alloys with an ultrahigh strength and ductility can be achieved via hot-rolling and tailoring Cu concentration, and the role of Cu concentration on the microstructure and texture evolution in the Zn-xCu alloys during hot-rolling were investigated by XRD, EBSD and TEM analysis. The results show that the microstructure of as-cast Zn-xCu alloys consisted of large sized CuZn₅ phase and Zn matrix grains before hot-rolling, and numerous submicron CuZn₅ phase can dynamically precipitate during hot-rolling of Zn-xCu alloys. The existence of CuZn₅ phase can result in the particle stimulated nucleation of recrystallization (PSN), and then result in the formation of fine recrystallized grains. Moreover, three texture components including $\left(0001\right)<11\overline{2}0>$, $\left(10\overline{1}1\right)<\overline{1}012>$ and $\left(11\overline{2}0\right)<0001>$ textures can form in the Zn-xCu alloys after hot-rolling. With boosting Cu concentration, the intensity of $\left(11\overline{2}0\right)<0001>$ texture gradually reduced, while the intensity of $\left(0001\right)<11\overline{2}0>$ and $\left(10\overline{1}1\right)<\overline{1}012>$ texture components firstly raised with the augment of Cu concentration, and then reduced. For the Zn-xCu alloys with 8 wt%Cu concentration, a combination of high yield strength, ultimate tensile strength and elongation (269.7 MPa, 322.9 MPa and 26.3 %) can be achieved, which can meet the high-performance demands of biodegradable metal vascular stents.