Abstract
In this study, we prepared zinc wires with a diameter of 250 µm by direct extrusion using an extrusion ratio of 576. We studied the influence of the extrusion temperature and microstructure of the initial Zn billets on the microstructural and mechanical characteristics of the extruded wires. The extrusion temperature played a significant role in the final grain size. The wires extruded at 300 °C possessed a coarse-grained microstructure and the shape of their tensile stress–strain curves suggested that twinning played an important role during their deformation. A significant influence of the initial grain size on the final microstructure was observed after the extrusion at 100 °C. The wires prepared from the billet with a very coarse-grained microstructure possessed a bimodal grain size. A significant coarsening of their microstructure was observed after the tensile test. The wires prepared from the medium-grained billets at 100 °C were relatively coarse-grained, but their grain size was stable during the straining, resulting in the highest ultimate tensile strength. This preliminary study shows that strong attention should be paid to the extrusion parameters and the microstructure of the initial billets, because they significantly influence the microstructure and mechanical behavior of the obtained wires.
Highlights
Zinc and Zn-based materials have been extensively studied as absorbable materials for medical applications [1,2,3,4,5]
Because pure zinc is very sensitive to any mechanical deformation and it can recrystallize even at low temperatures, the crossand longitudinal sections were prepared by ion machining using Xe focused ion beam milling (FIB)
Because thin metallic wires are considered for the fabrication of absorbable sutures [21], it is important for the wires to be able to be knotted without any damage to the wire
Summary
Zinc and Zn-based materials have been extensively studied as absorbable materials for medical applications [1,2,3,4,5]. Cast zinc is usually coarsegrained; the increasing grain size decreases the critical resolved shear stress (CRSS) for twinning, which is the predominant deformation mechanism in coarse-grained Zn-based materials [9]. The medium-grained Zn-based materials deform mainly by dislocation slip, which results in an increase in both strength and ductility [9,12]. The aforementioned suggests that a suitable adjustment of the grain size can alter the mechanical performance to be closer to the values desired for applications. Thermomechanical treatments, such as extrusion, rolling or equal channel angular pressing, are powerful tools for grain refinement [14]. The influence of the extrusion temperature and microstructure of the starting Zn blocks on the microstructure and mechanical properties of the extruded Zn wires will be discussed
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