چكيده به لاتين
Extensive studies have been published on the potential of zinc and its alloys as biocompatible alloys for the production of biodegradable implants and stents. These preliminary in vitro and in vivo studies showed better mechanical performance and good biocompatibility as well as lower corrosion rates than Mg-based biocompatible metals. The most important limitation of using pure zinc as an implant is its poor mechanical strength. For this purpose, in this study, the effect of Cu on the microstructure and mechanical properties of Zn-xCu alloy is investigated. The as-cast Zn-xCu (x=1, 2, and 3.5 wt%, denoted as Zn-1, 2, 3, 4Cu, respectively) alloy was prepared and then homogenized at about 360 °C for 8 h, followed by quenching in water. Phase constituents were analyzed using X ray diffraction. Scanning Electron Microscope images show that as the Cu content increases, more CuZn5 phase precipitates. Optical microscope(OM) and Scanning Electron Microscope (SEM) images show that as the Cu content increases, more CuZn5 phase precipitates. The extrusion was performed on Zn-xCu alloys with speed of 2 mm / min at a temperature of 240 ° C to improve microstructure and mechanical properties. After extrusion, the CuZn5 phases are broken and the grains of Zn-xCu alloys are refined. Tensile test shows that Cu addition could significantly improve the mechanical properties of Zn-xCu alloys. The tensile properties the Zn-xCu alloys are enhanced gradually. The highest YS and UTS and elongation values are reached by Zn-3.5Cu alloy, which are about 215 MPa, 234 MPa and 46% respectively, which meet the general design criteria for cardiovascular stents. Aging heat treatment was performed to improve mechanical properties at 90 and 120 ° C for Zn-1Cu and Zn-2Cu alloys.
