“…Fig. 3 shows mechanical property of ZN20 alloy wires in this study and some typical Mg alloy wires in recent studies [ [25] , [26] , [27] , [28] , [29] ]. These magnesium alloy wires exhibit two characteristics: high strength with lower ductility or good ductility with lower strength.…”
Section: Resultsmentioning
confidence: 91%
“… Fig. 3 The stress-strain curves of the experimental ZN20 alloys at room temperature (a) and comparison of ultimate tensile strength vs. elongation for present ZN20 alloy wires and recent developed magnesium alloy wires (b) [ [25] , [26] , [27] , [28] , [29] ]. Fig.…”
Titanium and its alloy are commonly used as surgical staples in the reconstruction of intestinal tract and stomach, however they cannot be absorbed in human body, which may cause a series of complications to influence further diagnosis. Magnesium and its alloy have great potential as surgical staples, because they can be degraded in human body and have good mechanical properties and biocompatibility. In this study, Mg-2Zn-0.5Nd (ZN20) alloy fine wires showed great potential as surgical staples. The ultimate tensile strength and elongation of ZN20 alloy fine wires were 248 MPa and 13%, respectively, which could be benefit for the deformation of the surgical staples from U-shape to B-shape. The bursting pressure of the wire was about 40 kPa, implying that it can supply sufficient mechanical support after anastomosis. Biochemical test and histological analysis illustrated good biocompatibility and biological safety of ZN20 alloy fine wire. The residual tensile stress formed on the outside of ZN20 fine wire during drawing would accelerate the corrosion. The second phase had a negative influence on corrosion property due to galvanic corrosion. The corrosion rate
in vitro
was faster than that
in vivo
due to the capsule formed on the surface of ZN20 alloy fine wire.
“…Fig. 3 shows mechanical property of ZN20 alloy wires in this study and some typical Mg alloy wires in recent studies [ [25] , [26] , [27] , [28] , [29] ]. These magnesium alloy wires exhibit two characteristics: high strength with lower ductility or good ductility with lower strength.…”
Section: Resultsmentioning
confidence: 91%
“… Fig. 3 The stress-strain curves of the experimental ZN20 alloys at room temperature (a) and comparison of ultimate tensile strength vs. elongation for present ZN20 alloy wires and recent developed magnesium alloy wires (b) [ [25] , [26] , [27] , [28] , [29] ]. Fig.…”
Titanium and its alloy are commonly used as surgical staples in the reconstruction of intestinal tract and stomach, however they cannot be absorbed in human body, which may cause a series of complications to influence further diagnosis. Magnesium and its alloy have great potential as surgical staples, because they can be degraded in human body and have good mechanical properties and biocompatibility. In this study, Mg-2Zn-0.5Nd (ZN20) alloy fine wires showed great potential as surgical staples. The ultimate tensile strength and elongation of ZN20 alloy fine wires were 248 MPa and 13%, respectively, which could be benefit for the deformation of the surgical staples from U-shape to B-shape. The bursting pressure of the wire was about 40 kPa, implying that it can supply sufficient mechanical support after anastomosis. Biochemical test and histological analysis illustrated good biocompatibility and biological safety of ZN20 alloy fine wire. The residual tensile stress formed on the outside of ZN20 fine wire during drawing would accelerate the corrosion. The second phase had a negative influence on corrosion property due to galvanic corrosion. The corrosion rate
in vitro
was faster than that
in vivo
due to the capsule formed on the surface of ZN20 alloy fine wire.
“…As illustrated in figure 10, the corrosion potential of the Ag 17 Mg 54 phase moves to a positive electrode due to the Ag addition [30,46]. Therefore, the surface microgalvanic corrosion is shifted to a circumstance which could lead to faster homogeneous corrosion and minimize pitting corrosion [29,46]. Pitting corrosion was controlled by this effect, which can explain why the 1Ag and 2Ag alloy can exhibit a less pitting corrosion susceptibility than 0Ag alloy displayed in figure 8.…”
Section: Discussionmentioning
confidence: 97%
“…The Volta potential of the second phase is about −30∼−50 mV, which is obviously lower than that of the matrix. As illustrated in figure 10, the corrosion potential of the Ag 17 Mg 54 phase moves to a positive electrode due to the Ag addition [30,46]. Therefore, the surface microgalvanic corrosion is shifted to a circumstance which could lead to faster homogeneous corrosion and minimize pitting corrosion [29,46].…”
In the anastomotic surgery, the currently used degradable magnesium alloys are facing some bottleneck problems such as lower mechanical properties and slower degradation rate. In this study, the novel biodegradable extruded Mg-1Zn-0.2Ca-xAg (x=0, 1, 2, 4) alloys will be developed and the corresponding microstructure, mechanical, and corrosion properties after Ag addition will be investigated. The results indicate that with the Ag addition, the grain size is refined due to fully dynamic recrystallization and Ag 17 Mg 54 phase, an important strengthening phase, begin to be precipitated in the Ag-contained alloys. Due to the stronger solution strengthening and precipitation strengthening, the Mg-1Zn-0.2Ca-4Ag alloy attains the highest ultimate tensile strength among all the alloys. Moreover, Ag element also enhances the electrode potential of the matrix, reduces the susceptibility of pitting corrosion and accelerates the corrosion rate of the alloys by micro-galvanic corrosion between the second phases and the matrix from the analyses of corrosion products and 3D Volta potential map. As a result, 4Ag alloys attain the fastest degradation rate among all the alloys. Combing the mechanical and corrosion results, it can be seen that 4Ag alloys, as novel biodegradable magnesium alloys, can meet the requirement of anastomotic surgery preferably, exhibiting the better application prospects.
“…While magnesium alloys do have some disadvantages, including a fast corrosion rate and poor mechanical properties, these can typically be improved by alloying, deformation, and surface modification [8][9][10]. Indeed, Zn, Ca, and Sr have been studied as alloying elements of magnesium alloys implanted in bone and have demonstrated good biocompatibility [11][12][13].…”
Recent advancements in bone implant materials have led to the development of various alloys. In this study, the degradation behavior of the as-cast Mg-3 wt% Zn-1 wt% Ca-0.5 wt% Sr alloy in vitro was investigated using x-ray diffraction (XRD), scanning Kelvin probe force microscopy (SKPFM), and scanning electron microscopy (SEM). Our results demonstrated that the alloy microstructure was composed of α-Mg, a Ca 2 Mg 6 Zn 3 phase, and a Mg 17 Sr 2 phase. The Ca 2 Mg 6 Zn 3 phase, which had the smallest absolute potential, was shown to have cathodic protection, while the α-Mg, which had the largest absolute potential, was shown to prefer corrosion. The in vitro corrosion products of the as-cast alloy were Mg(OH) 2 , a Ca-P compound, and HA. At the beginning of the corrosion, the hydrogen evolution rate of the alloy was fast due to the thin corrosion product layer. With the extension of the corrosion time, the corrosion layer thickened and the hydrogen evolution rate slowed down and stabilized to 1.25×10 −5 mol cm −2 ·h . Due to the high concentration of Ca and Mg ions near the second phase, HA was quickly deposited and an ion exchange channel between the solution and the alloy was formed, making it easier for the Mg, Ca, and Sr ions to enter the solution and promote the formation of HA. The hysteresis effect of Sr element was found, that is, Sr ions were released into the solution after etching for a period of time, which promoted the formation of HA and HA-containing Sr (Sr/HA).
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