Low-alloyed magnesium alloy with high ductility and high damping capacities at room temperature and preparation method thereof
A low-alloyed magnesium (Mg) alloy with high ductility and high damping capacities at room temperature and a preparation method thereof are provided. The low-alloyed Mg alloy with high ductility and high damping capacities includes the following elements in percentage by mass: 0.5-1.5% of Gadolinium (Gd), 0.5-0.9% of Zinc (Zn), 0.3-0.6% of Zirconium (Zr), and the balance of Mg (Mg). By adding low-content Gd, Zn and Zr elements to a Mg matrix, the low-alloyed Mg alloy not only has effects of solid solution strengthening, precipitation strengthening and fine-grain strengthening, but also, under the interaction effect of a plurality of elements, promotes the non-basal dislocation slipping of Mg alloy, and stimulates the dislocation damping mechanism, thereby effectively improving the plasticity and damping properties of Mg alloy. The low-alloyed Mg alloy with high ductility and high damping capacities at room temperature has excellent plasticity and damping properties at room temperature.
1 . A preparation method of a magnesium (Mg) alloy, wherein the Mg alloy consists of the following elements in percentage by mass:
0.6-1.4% of gadolinium (Gd),
0.6-0.8% of zinc (Zn),
035-0.55% of zirconium (Zr), and
a balance of Mg,
a mass ratio of the Gd to the Zn in the Mg alloy is 1.0≤Gd/Zn≤3.0, and
a mass percentage of impurity elements in the Mg alloy is equal to or less than 0.1%; and
the preparation method of the Mg alloy comprises the following steps:
(1) sequentially melting, refining, keeping static, and semi-continuous casting alloy raw materials to obtain a Mg alloy ingot, wherein the refining is performed by inflating with argon gas, the semi-continuous casting is performed under a mixed CO 2 and SF 6 gas atmosphere; and
(2) sequentially performing a homogenization annealing and an extrusion of the Mg alloy ingot obtained in the step (1) to obtain the Mg alloy;
wherein a temperature of the keeping static in the step (1) is 720-730° C., and a time of the keeping static is 30-90 min.
2 . The preparation method according to claim 1 , wherein the impurity elements comprise iron (Fe), silicon (Si), copper (Cu), and nickel (Ni), wherein a mass percentage of the Fe is equal to or less than 0.03%, a mass percentage of the Si is equal to or less than 0.03%, a mass percentage of the Cu is equal to or less than 0.01%, and a mass percentage of the Ni is equal to or less than 0.01%.
3 . The preparation method according to claim 1 , wherein a temperature of the refining in the step (1) is 720-730° C., and a time of the refining is 5-15 min.
4 . The preparation method according to claim 1 , wherein a temperature of the semi-continuous casting in the step (1) is 705-715° C., a speed of the semi-continuous casting is 100-300 mm/min, and a circulating water flow rate of the semi-continuous casting is 5-25 m 3 /h.
5 . The preparation method according to claim 1 , wherein a holding temperature of the homogenization annealing in the step (2) is 480-530° C., and a holding time of the homogenization annealing is 20-30 h.
6 . The preparation method according to claim 1 , wherein a temperature of the extrusion in the step (2) is 350-450° C., a ratio of the extrusion is equal to or greater than 20, and a speed of the extrusion is 0.2-10 m/min.
7 . The preparation method according to claim 1 , wherein the Mg alloy obtained in the step (2) has an ultimate tensile strength of 215-256 MPa, a tensile yield strength of 128-211 MPa, an elongation of 31.7-39.3% at room temperature, and a damping capacity (Q −1 ) of 0.02-0.035, wherein the damping capacity is expressed by the reciprocal Q −1 of the quality factor at a strain of 10 −3 .