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Mechanical properties, crystallographic texture, and in vitro bio-corrosion of low-alloyed Zn–Mg, produced by hot and cold drawing for biodegradable surgical wires

Milenin Andrij, Wróbel Mirosław, Kustra Piotr, Packo Marek, Byrska‑Wójcik Dorota, Sulej-Chojnacka Joanna, Płonka Bartłomiej

Archives of Civil and Mechanical Engineering

2021

Vol. 21, no. 4

479--492

The paper is devoted to the study of the mechanical, microstructural, and bio-corrosive behavior of low-alloyed Zn–Mg biodegradable surgical wires for bone reconstructions. Three biodegradable alloys with different magnesium content have been studied, their production technology has been developed and the product properties have been determined. The technology includes casting, extrusion, hot and cold drawing of the wire, and the product surface finishing. The paper shows the most important stages of the process (i.e., extrusion and drawing) in detail. The technological parameters have been selected based on the results of the computer modeling. The flow stress–strain curves of extruded materials have been obtained at various strain rates and temperatures. Two drawing technologies have been compared. The first one is the room temperature conventional wire drawing. In the second one, the first few passes have been made at an elevated temperature and the rest at room temperature. This allowed avoiding the breaking of the wire during the first passes (a typical issue of the conventional technology for these alloys) and increasing the ductility of the final product. Mechanical properties, bio-corrosion, and crystallographic texture of the material were determined at different stages of the processing. A simultaneous increase in the wire strength, the number of repeated bending until the rupture of the wire, and in the bio-corrosion rate due to drawing has been registered. This phenomenon coincided with a change in the crystallographic texture. It has been shown that the product tensile strength of about 250–300 MPa can be reduced by about 30% due to surgical knots tied on it.

The effect of in vitro corrosion on the mechanical properties of metallic high strength biodegradable surgical threads

Milenin Andrij, Kustra Piotr, Byrska-Wójcik Dorota, Wróbel Mirosław, Paćko Marek, Sulej‑Chojnacka Joanna, Matuszyńska Sława, Płonka Bartłomiej

Archives of Civil and Mechanical Engineering

2020

Vol. 20, no. 2

437--452

High strength biodegradable surgical threads are in demand for surgical practice. Nowadays, such threads can be made of metallic materials such as magnesium, zinc or alloys based on these metals. In current paper, manufacturing technology of biodegradable surgical threads of Mg–Ca alloys and of pure Zn was developed and basic properties of the obtained product have been characterized. The influence of in vitro corrosion in bovine serum simulating environment in the mammal’s body on the surgical threads mechanical properties was determined. It was found that Zn and hot extruded alloys MgCa0.9 and MgCa1.2 can be recommended as a candidate for the future study in vivo. Properties of the room temperature drawn wires of the alloy MgCa0.7 are not sufficient for its application as surgical threads.

Symulacje oraz weryfikacja eksperymentalna matryc przeznaczonych do wyciskania stopów trudno odkształcalnych

Korczak Piotr, Płonka Bartłomiej, Remsak Krzysztof, Leśniak Dariusz

Rudy i Metale Nieżelazne Recykling

2019

R. 64, nr 4

17--20

W badaniach wykorzystano oprogramowanie do symulacji MES (program Q-form) do lepszego zrozumienia charakterystyki płynięcia stopów twardych w procesie wyciskania oraz wytypowania kluczowych parametrów mających wpływ na maksymalne uzyskiwane wydajności w procesie. W tym celu przygotowano szereg symulacji różnych geometrii matryc, zapewniających dużą rozpiętość warunków tarcia oraz gradientu prędkości płynięcia materiału. Pozwoliło to na wstępną weryfikację i wykonanie wspomnianych narzędzi, które przetestowane zostały w warunkach eksperymentalnych. Kluczowym wynikiem badań było skorelowanie maksymalnych prędkości wyciskania z zaprojektowanymi geometriami narzędzi.

The paper presents the results of using the MES software (Q-form program) to better understand the flow characteristics of hard alloys in the extrusion process and to identify key parameters affecting the maximum efficiency achieved in the process. A series of different die geometry simulations have been prepred to achieve a large range of friction conditions and a material flow gradient. The key result of the work was to correlate the maximum extrusion speed with the designed tool geometries.