The invention provides a method for preparing a foamed
magnesium alloy through secondary foaming. The method includes the following steps that firstly,
magnesium is heated till being molten, the temperature is regulated to 700 DEG C to 750 DEG C, a
tackifier accounting for, by
mass, 0.5%-3.0% of the molten
magnesium is added, and stirring is conducted for 5 min to 15 min at the rotating speed
ranging from 600 rpm to 800 rpm, wherein the
tackifier is composed of 40 wt%-60 wt% of
calcium oxide and 30 wt%-55 wt% of magnesium
carbonate; secondly, the melt obtained in the first step is cooled to 580 DEG C to 620 DEG C,
calcium carbonate powder accounting for, by
mass, 2%-10% of the molten magnesium is added, stirring is stopped after being conducted for 3 min to 7 min at the rotating speed
ranging from 800 rpm to 1500 rpm, the temperature is lowered to 300 DEG C to 500 DEG C, and heat preservation is conducted for 20 min to 30 min; and thirdly, the temperature then rises to 800 DEG C to 900 DEG C so that the
calcium carbonate in a blank can be subjected to secondary
thermal decomposition and secondary foaming, after the mixture is stirred to be uniform,
water cooling is conducted till the
room temperature is achieved, and the foamed
magnesium alloy is obtained. The foamed
magnesium alloy prepared through the method can be used for preparing special-shaped pieces complex in appearance, and is uniform in pore size distribution and good in
flame retardant property.