Mg−Nd−Zn−Zr magnesium alloy(JDBM)has been studied widely as biodegradable medical material.To process high quality JDBM wires,effects of annealing on the mechanical properties and degradation behavior after drawing we...Mg−Nd−Zn−Zr magnesium alloy(JDBM)has been studied widely as biodegradable medical material.To process high quality JDBM wires,effects of annealing on the mechanical properties and degradation behavior after drawing were studied by microscopic observations,tensile and immersion tests.The as-extruded wires with a diameter of 3 mm could be drawn up to 9 passes without annealing until 125%cumulative drawing deformation.Complete recrystallization occurred after annealing at 325℃ for 30 min,350℃ for 5 min or 450℃for 3 min,respectively.Room temperature tensile tests and simulated body fluid immersion tests showed that annealing at slightly elevated temperature for short time could obtain better properties due to the finer grain size and more dispersive distribution of precipitates.For this study,annealing at 350℃ for 5 min is the best parameters which can be utilized to further fabricate fine wires.展开更多
The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical propertie...The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical properties,Sr Zn13 phase was newly formed due to the addition of 0.1 wt.%Sr,improving the yield strength,ultimate tensile strength and elongation from(85.33±2.86)MPa,(106.00±1.41)MPa and(15.37±0.57)%for pure Zn to(107.67±2.05)MPa,(115.67±2.52)MPa and(20.80±2.19)%for Zn-0.1Sr,respectively.However,further increase of Sr content led to the deterioration of the mechanical properties due to the stress concentration and cracks initiation caused by the coarsening Sr Zn13 particles during tensile tests.For in vitro degradation,since micro galvanic corrosion was enhanced owing to the formation of the inhomogeneously distributed Sr Zn13 phase,the corrosion mode became non-uniform.Corrosion rate is gradually increased with the addition of Sr,which is increased from(11.45±2.02)μm/a(a=year)for pure Zn to(32.59±3.40)μm/a for Zn-0.8Sr.To sum up,the as-extruded Zn-0.1Sr alloy exhibited the best combination of mechanical properties and degradation behavior.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.U1804251)the Shanghai Municipal Commission of Economy and Information,China(No.GYQJ-2019-1-27)+2 种基金the Science and Technology Commission of Shanghai Municipality,China(Nos.18441908000,19441906300,19441913400)the Shenzhen’s Three Renowned Project,China(No.SZSM201612092)the Shanghai Jiao Tong University Medical-engineering Cross Fund,China(No.YG2019ZDA02).
文摘Mg−Nd−Zn−Zr magnesium alloy(JDBM)has been studied widely as biodegradable medical material.To process high quality JDBM wires,effects of annealing on the mechanical properties and degradation behavior after drawing were studied by microscopic observations,tensile and immersion tests.The as-extruded wires with a diameter of 3 mm could be drawn up to 9 passes without annealing until 125%cumulative drawing deformation.Complete recrystallization occurred after annealing at 325℃ for 30 min,350℃ for 5 min or 450℃for 3 min,respectively.Room temperature tensile tests and simulated body fluid immersion tests showed that annealing at slightly elevated temperature for short time could obtain better properties due to the finer grain size and more dispersive distribution of precipitates.For this study,annealing at 350℃ for 5 min is the best parameters which can be utilized to further fabricate fine wires.
基金Project(17XD1402100)supported by the Science and Technology Commission of Shanghai Municipality,ChinaProject(SZSM201612092)supported by Shenzhen Three Renowned Project,China+1 种基金Project(2018RC001A-18)supported by the Innovation Talent Program of Karamay City,ChinaProject(2018D01A07)supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China。
文摘The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical properties,Sr Zn13 phase was newly formed due to the addition of 0.1 wt.%Sr,improving the yield strength,ultimate tensile strength and elongation from(85.33±2.86)MPa,(106.00±1.41)MPa and(15.37±0.57)%for pure Zn to(107.67±2.05)MPa,(115.67±2.52)MPa and(20.80±2.19)%for Zn-0.1Sr,respectively.However,further increase of Sr content led to the deterioration of the mechanical properties due to the stress concentration and cracks initiation caused by the coarsening Sr Zn13 particles during tensile tests.For in vitro degradation,since micro galvanic corrosion was enhanced owing to the formation of the inhomogeneously distributed Sr Zn13 phase,the corrosion mode became non-uniform.Corrosion rate is gradually increased with the addition of Sr,which is increased from(11.45±2.02)μm/a(a=year)for pure Zn to(32.59±3.40)μm/a for Zn-0.8Sr.To sum up,the as-extruded Zn-0.1Sr alloy exhibited the best combination of mechanical properties and degradation behavior.
