Effect Of Zn And Sr On Microstructure,Mechanical Properties And Biocorrosion Behavior Of Mg-Si Alloy

Compared with traditional metallic biomaterials,magnesium and magnesium alloys are favored as potential degradable metallic biomaterials due to their superior mechanical properties and good biocompatibility.However,in the specific environment of the human body,magnesium and magnesium alloys are degraded too fast in the body,shortening their service life in the body and bringing physical discomfort to the human body possibly,which restricts it from wide application in the field of biological materials.In order to explore a new medical magnesium alloy with excellent mechanical properties and good corrosion resistance in this paper,Mg-1.38Si alloys are treated in modification,thus,Sr and Zn elements which have good biocompatibility,improve the mechanical properties and corrosion resistance of medical degradable magnesium alloys are selected as alloy elements,then,Mg-1.38Si-xSr/Zn and Mg-1.38Si-1.5Zn-xSr alloys are designed.It was investigated that Sr and Zn elementsinfluence on the microstructure,mechanical properties and corrosion behavior of the biodegradable magnesium alloys.?1?The Mg-xSi alloys are mainly composed of?-Mg and Mg₂Si phase.With the increasing of the content of Si,The microstructure is gradually coarsened and the number of Mg₂Si phase increases.With the increasing of the content of Si,it can be found that significant increase in yield strength,ultimate tensile strength,compressive fracture strength and hardness are found but slight decrease in elongation and plastic deformation rate are observed.With the increasing of the content of Si,it can be found that decrease in bio-corrosion resistance of alloys is observed by immersion experiment and electrochemical experiment.?2?The Mg-1.38Si-xSr alloys are mainly composed of?-Mg and Mg₂Si phase.With the increasing of the content of Sr,the morphology of the primary Mg₂Si phase can be changed from coarse polygonal shape to the fine particle shape,and the eutectic Mg₂Si phase can be changed from coarse Chinese script to a short rod.With the increasing of the content of Sr,it can be found that first increase and then decrease in yield strength,tensile strength and elongation are found but slight increase in compressive fracture strength and plastic deformation are observed.With the increasing of the content of Si,it can be found that decrease in bio-corrosion resistance of alloys is observed by immersion experiment and electrochemical experiment.?3?The Mg-1.38Si-xZn alloys are mainly composed of?-Mg and Mg₂Si phase.When 1.5wt.%Zn is added,the Mg₂Si phase is refined.With further increase of Zn content to 2wt.%,the Mg₂Si phase is coarsened.With the increasing of the content of Zn,it can be found that first increase and then decrease in hardness,yield strength,tensile strength,elongation,compressive fracture strength and plastic deformation were observed.When 1.5wt.%Zn is added,the best mechanical properties are observed.With the increasing of the content of Zn,it can be found that increase first and then decrease in bio-corrosion resistance of alloys is observed by immersion experiment and electrochemical experiment.?4?The Mg-1.38Si-1.5Zn-xSr alloys are mainly composed of?-Mg and Mg₂Si phase.With the increasing of the content of Sr,the morphology of the Mg₂Si phase can be changed from coarse Chinese script to a short rod.With the increasing of the content of Sr,it can be found that first decrease and then increase in yield strength,tensile strength and elongation were found but slight increase in compressive fracture strength and plastic deformation were observed.With the increasing of the content of Sr,it can be found that slight decrease in bio-corrosion resistance of alloys is observed by immersion experiment and electrochemical experiment.