from the conferences organized by TANGER Ltd. provisional website
The Mg – 2.2-3.8 wt.% Zn – 0.3-0.7 wt.% Ca – 0-0.9 wt.% Mn alloys as a material for the production of biodegradable implants was investigated. Equal-channel angular pressing (ECAP) to improve the grain structure and mechanical properties of the alloys was used. The microstructure and phase composition of alloys were determined using scanning electron microscopy and energy dispersive X-ray spectroscopy. The phase diagrams and alloys phase composition were calculated using the Thermo-Calc software. For the alloy sample, a differential thermal analysis (DTA) was carried out. The mechanical properties and corrosion properties of ECAP processed alloys were investigated. In vitro corrosion test by hydrogen evolution method was carried out in Hank’s solution. The alloys containing Mn were composed of primary solid solution (Mg), manganese particles (Mn) and eutectic (Mg) + (Mn) + Ca2Mg6Zn3. The alloys without Mn were composed of primary solid solution (Mg) and eutectic (Mg) + Ca2Mg6Zn3. The alloys have a wide equilibrium crystallization range of about 250 °С. The solute treatment of alloys leads to an increase of the zinc concentration in the (Mg) solid solution. Calcium and manganese are slightly soluble in (Mg) solid solution. The obtained samples of Mg-Zn-Ca and Mg-Zn-Ca-Mn alloys have ultimate strength (UTS) from 220 to 240 MPa, and elongation (El) from 17 to 29 % after ECAP. The corrosion test was executed for 192 hours. All investigated alloys showed approximately the same result. The manganese addition didn't affect the corrosion resistance of the investigated alloy after ECAP.Keywords: Biodegradable magnesium alloys, Mg-Zn-Ca-Mn, Mg-Zn-Ca, ECAP, corrosion
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