Rare earth magnesium alloy based on high-temperature and high-pressure hydrogenation and preparation method

A preparation method of a rare earth magnesium alloy based on high-temperature and high-pressure hydrogenation, comprising the following steps:

• (1) according to an elemental composition of the rare earth magnesium alloy, weighing and preheating pure magnesium, pure aluminum, and at least one of a Mg-30Gd master alloy and a Mg-30Y master alloy;
• (2) under protection of mixed gas, raising a furnace temperature to melt the pure magnesium to obtain molten magnesium;
• (3) under protection of mixed gas, raising the furnace temperature, adding at least one of the Mg-30Gd master alloy and the Mg-30Y master alloy, and adding the pure aluminum successively to the molten magnesium, skimming dross off, stirring, and allowing heat preservation to obtain a mixed melt;
• (4) under protection of mixed gas, lowering the furnace temperature, skimming surface dross off, and adding a refining agent to the mixed melt to obtain a rare earth magnesium alloy melt;
• (5) under protection of mixed gas, raising the furnace temperature, allowing static heat preservation, and skimming surface dross off to obtain a purified rare earth magnesium alloy melt;
• (6) under protection of mixed gas, lowering the furnace temperature, and when the purified rare earth magnesium alloy melt is cooled to a casting temperature, skimming surface dross off and casting the purified rare earth magnesium alloy melt into a preheated mold to obtain a rare earth magnesium alloy ingot;
• and
• (7) cutting the open shrinkage and surface oxide scale off from the rare earth magnesium alloy ingot, and conducting a hydrogenation treatment in a hydrogenation reactor to obtain the rare earth magnesium alloy based on the high-temperature and high-pressure hydrogenation,
• wherein in the step (1), the preheating is conducted at 190° C. to 210° C.;
• in the step (2), the furnace temperature is raised to 730° C. to 750° C.;
• in the step (3), the furnace temperature is raised to 750° C. to 770° C.;
• in the step (4), the furnace temperature is lowered to 730° C. to 750° C.;
• in the step (5), the furnace temperature is raised to 750° C. to 770° C.;
• in the step (6), the furnace temperature is lowered to 720° C. to 740° C., and during the casting, the purified rare earth magnesium alloy melt is at a temperature of 710° C. to 730° C. and the mold is preheated to 190° C. to 210° C.;
• in the step (7), the hydrogenation treatment is conducted for 35 h to 45 h at a temperature of 480° C. to 520° C. and a pressure of 0.5 MPa to 10 MPa;
• in the step (3), the heat preservation is allowed for 10 min to 20 min;
• in the step (5), the static heat preservation is allowed for 10 min to 15 min;
• the rare earth magnesium alloy comprises the following elements in mass percentages:
• 0 wt % to 23.5 wt % of gadolinium;
• 0 wt % to 12.5 wt % of yttrium;
• 0.1 wt % to 3 wt % of aluminum;
• and
• the balance of magnesium and unavoidable impurities;
• the rare earth magnesium alloy based on high-temperature and high-pressure hydrogenation comprises at least one of gadolinium and yttrium;
• and
• the unavoidable impurities in mass percentages are as follows:
• less than or equal to 0.01 wt % of iron;
• less than or equal to 0.0054 wt % of nickel;
• and
• less than or equal to 0.005 wt % of copper.