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 0001<112((sic))0>, 101<overline>1<1((sic))012> and 112((sic))0<0001> textures can form in the Zn-xCu alloys after hot-rolling. With boosting Cu concentration, the intensity of 112<overline>0<0001> texture gradually reduced, while the intensity of 0001<112((sic))0> and 101((sic))1<1((sic))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.