Grain refinement method of biodegradable Zn-1Mg-0.5Ca casting alloy

The invention belongs to the field of medical degradable implant materials for human bodies, and relates to a grain refinement method of a biodegradable zinc-magnesium-calcium (Zn-1Mg-0.5Ca) casting alloy. The invention aims to solve the problem that alloy elements harmful to a human body are easily caused when a zinc-magnesium-calcium casting alloy casting structure is refined by an existing method of adding a refiner. The invention discloses the grain refinement method of the biodegradable casting alloy, the prepared alloy is remelted, and then high-energy ultrasonic treatment is carried out on the melted alloy melt under a low-temperature condition. According to the cast alloy subjected to ultrasonic melt treatment, the alpha-Zn morphology is refined into fine isometric crystals from coarse dendrites, and the average size of crystal grains is reduced to 10 microns; the second dimension of the formed CaZn13 is reduced, and the CaZn13 is uniformly distributed on an alloy matrix, so that the improvement of th