Influence of Ca addition on microstructure, mechanical properties and corrosion behavior of Mg-2Zn alloy

Abstract

D ue to low Young's modulus (~45GPa), low density (1.7-2.0 g•cm-3), and good biodegradable properties, magnesium and magnesium alloys are in a region of interest as potential orthopedic, craniofacial, and cardiovascular materials [1]. Many researchers are currently developing new biodegradable magnesium alloys and investigating all kinds of properties [2]. Among all the alloys, Mg-Zn-Ca especially attracts the scientists' attention because of their high strength (yield strength>200 MPa, ultimate tensile strength>250MPa), high ductility (elongation>20%), moderate bio-corrosion properties, and good biocompatibility [3, 4]. Summarizing the development status of Mg-Zn-Ca alloys, it is found that Zn content generally surpasses or equals to 4wt.% if Ca addition is less than 1wt.% [1,5-13] or Zn concentration <10wt.% if Ca addition is ≥1wt. % [14-20]. The purpose of high Zn addition is to ensure high mechanical properties by solid-solution strengthening, grain boundary strengthening and precipitation strengthening, while the role of Ca is to refi ne the grain size and enhance the ignition point [21]. However, it is also noted that high Zn or high Ca concentration is generally detrimental to corrosion resistance [15, 22-25]. Therefore, the growing trend in

Effect of Microstructure Refinement on the Corrosion Behavior of the Bioresorbable Mg-1Zn-0.2Ca and Mg-1Ca Alloys

“…According to literature data, the α-Mg–Mg 2 Ca pair has a high electrochemical activity [ 23 ]. It can be seen from the surface structure that each large corrosion pit emerges at a location of eutectics and is a result of microgalvanic corrosion caused by the α-Mg–Mg 2 Ca interaction [ 31 ]. The surface adjacent to the striations is also covered by small pits, which indicates the simultaneous intensive corrosion of both the eutectics and the matrix ( Figure 5 b).…”

Improvement of microstructure, mechanical properties, and corrosion resistance of WE43 alloy by squeeze casting

“…The initial pH of Hank's solution was set to 7.4. In the pH experiment, Hank's solution was not changed, whereas in the weight loss experiment, Hank's solution was replaced every 24 h. For the weight loss experiment, the sample was removed from the (1) where constant K=8.76×10 4 , W is the weight loss (g), A is the area of the sample exposed to the solution (cm 2 ), T is the immersion time (h), and D is the density of the material (g•cm -3 ). A pH meter was used to record the pH at different time intervals.…”

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Magnesium alloys have become essential materials in aviation, automobile, computer, communication, and consumer electronics [1][2][3] . Due to their excellent biocompatibility and biodegradability, numerous studies have been conducted on magnesium alloys as medical materials [4][5][6] . As a biological magnesium alloy, WE43 alloy has been studied by many researchers [7][8][9][10] .

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Microstructure, mechanical and corrosion properties of novel quaternary biodegradable extruded Mg–1Zn–0.2Ca-xAg alloys

“…Although the extruded REcontaining alloys exhibited better performance in the mechanical properties in particular, for instance, Mg-2.4Zn-0.8Gd alloy with a tensile yield strength (TYS) of 284 MPa and ultimate tensile strength (UTS) of 338 MPa [14], RE-free Mg alloys are more competitive for commercial utilization because of the biosafety [15]. According to our recent investigations [16][17][18], Mg-1.0Zn-0.2Ca alloy is promising as the base alloy for further alloy development if considering comprehensive mechanical and corrosion properties although its mechanical properties are still not enough for medical application.…”

“…The microstructure of extruded Mg-1Zn-0.2Ca-xAg alloys observed by OM perpendicular to the extruded direction: (a) 0Ag; (b) 1Ag; (c) 2Ag; (d) 4Ag.0.25 μm size can be speculated to be the binary Ag17 Mg 54 phase for the 1Ag alloy from the corresponding SADPs manifested in figure 4(f). The second phase in the 2Ag alloy, shown in figure 4(c), keep roughly as same as that of 1Ag alloy no matter the morphology or the component.…”