The Relationship Between Microstructure And Bio-corrosion Resistance Property Of ZM61Ca0.5Alloy

In the past40years, biomaterials made a great contribution for the treatment ofdisease and relieve suffering, stainless steel, cobalt-based alloys, titanium alloys aremore mature biological materials at present.Medical materials have been used in morethan eight thousand kinds of medical devices,but none of them can satisfy all theproperties of its clinical applications.Therefore, further design and development of newbiomedical materials is very necessary.As a biological material, magnesium alloy has its unique advantage,for example,excellent mechanical compatibility, biocompatibility and biodegradable, somebiological problems such as "shielding effectiveness"、"side effects" and "secondsurgery" will be effectively addressed, therefore, magnesium alloy is expected tobecome a new generation of biomaterials which has perfect performance.But the poorcorrosion resistance is the disadvantage of the magnesium alloy, which hinders itsfurther development.This paper expects to improved ZM61Ca0.5magnesium alloycorrosion resistance in the simulated body fluid by hot extrusion and heat treatment.Theresults showed that:①Hot extrusioncan greatly improve the organizational structure of ZM61Ca0.5magnesium alloy.With the increase of the extrusion ratio,microstructure was continuallyrefined,when the extrusion ratio is10,grain and second is sufficiently refined.②The corrosion resistance of ZM61Ca0.5magnesium in simulated body fluid wasimproved by hot extrusion.When the extrusion ratio was10, the corrosion resistance isbest.③The corrosion resistance of ZM61Ca0.5magnesium in simulated body fluid wasfurther improved by heat treatment,under the condition of this experiment, thecorrosion resistance of alloy after330℃×8h＋380℃×16hgrading annealing was best.④The mechanical properties of ZM61Ca0.5magnesium alloy was improvedthough hot extrusion and heat treatment. Tensile strength, yield of mild, ductility andhardness of the as-cast alloy were significantly improved through hot extrusion,whenthe extrusion ratio reached10, the microhardness of the alloy is81.5HV, tensile strengthis280MPa,yield strength is170MPa, elongation is13.5%;heat treatment furtherimproved the mechanical properties of the alloy,after aging, the tensile strength of thealloy is300MPa, yield strength is230MPa, elongation rate is10.1%. ⑤The toxicity of ZM61Ca0.5magnesium alloy at as-cast, extruded, annealing andaging conditions were tested through the MTT experiment, results show that the alloyhas good biological safety.