The influence of Ca and Cu additions on the microstructure, mechanical and degradation properties of Zn-Ca-Cu alloys for absorbable wound closure device applications.

Novel ternary Zn-Ca-Cu alloys were studied for the development of absorbable wound closure device material due to Ca and Cu's therapeutic values to wound healing. The influence of Ca and Cu on the microstructure, mechanical and degradation properties of Zn were investigated in the as-cast state to establish the fundamental understanding on the Zn-Ca-Cu alloy system. The microstructure of Zn-0.5Ca-0.5Cu, Zn-1.0Ca-0.5Cu, and Zn0.5Ca-1.0Cu is composed of intermetallic phase CaZn distributed within the Zn-Cu solid solution. The presence of CaZn phase and Cu as solute within the Zn matrix, on the one hand, exhibited a synergistic effect on the grain refinement of Zn, reducing the grain size of pure Zn by 96%; on the other hand, improved the mechanical properties of the ternary alloys through solid solution strengthening, second phase strengthening, and grain refinement. The degradation properties of Zn-Ca-Cu alloys are primarily influenced by the micro-galvanic corrosion between Zn-Cu matrix and CaZn phase, where the 0.5% and 1.0% Ca addition increased the corrosion rate of Zn from 11.5 μm/y to 19.8 μm/y and 29.6 μm/y during 4 weeks immersion test.