Biodegradable magnesium alloy without rare earth elements, preparation method and use thereof

A method for preparing a biodegradable magnesium alloy without rare earth elements, wherein the biodegradable magnesium alloy without rare earth elements comprises the following elements in percentage by mass:

• Zn
• 1.0-5.0%;
• Mn
• 0.1-1.0%;
• Ca
• 0.1-1.0%;
• Sr
• 0.1-1.0%;
• Sn
• 0.1-3.0%;
• Zr
• 0.1-0.8%;
• and
• Mg
• balance[[;]],
• wherein, the magnesium alloy has an average grain size of 5-10 μm, and an average density of crack distribution on the surface of the magnesium alloy is less than or equal to 20 cracks/mm2,
• the method specifically comprising the steps of:
• 1) melting-casting:
• in a closed container, fully adding each metal powder into a melting ladle according to the required proportion, controlling the temperature to melt at 700-800° C., blowing argon and stirring, casting and cooling;
• 2) heat treatment:
• heating the alloy obtained by casting, controlling the temperature at 200-250° C., annealing for 1-5 min, and cooling;
• 3) hot extrusion:
• putting the heat-treated alloy into a hot extrusion mold, controlling the temperature at 250-300° C., controlling the extrusion rate at 2-5 mm/s, and setting the extrusion ratio to 10-15:1;
• and
• 4) rolling and forming:
• rolling at a temperature of 320-350° C., controlling the speed at 20-30 m/min, and controlling the reduction of each rolling at 50-80%, to obtain a formed biodegradable magnesium alloy, and the magnesium alloy has a tensile strength and a yield strength greater than 250 MPa, which are measured according to GB-T228-2002, the magnesium alloy has a degradation rate of 1.35 mm/Y or less.