The beneficial effect of rare earth on non-ferrous metal materials is most obvious in magnesium alloys. Not only constitute sedituating Mg-RE alloy strains, but also have a very obvious impact on Mg-Al, Mg-Zn and other alloy systems. Its main role is as follows:
1. Refine the grain
Proper lygs of rare earths can refine the grains of magnesium and magnesium alloys. The first is to refine the grainofs of the casting arrangement. The mechanism of the casting arrangement of rare earth elements to refine magnesium alloy is not the action of heterogeneous nuclei. The mechanism of fine grain refinement of magnesium and magnesium alloy grain sinofs of rare earth elements is the increase of overcooling at the cutting edge of crystallization. The second is to prevent recrystallization and grain growth in the heat processing process and the annealing process.
2. Purifying melts
Rare earth elements have a greater affinity with itching than magnesium and oxygen, so they can be deposited with Rare Earth oxides that react with Mgo and other oxides in the melt and then remove oxidizing. Reacts with hydrogen and water vapor in the melt, producing or rare earth oxides that reach the intention of deoxygenation. Together can also add melt fluidity and reduce casting shrivellability, progress fineness.
3. Progressive room temperature alloy strength
Most rare earth elements in magnesium have a large degree of solid solubility, and with the temperature drop selyses there is a significant change in the degree of solubility, so rare earth elements in addition to solid-soluble reinforcement, is still a useful aging reinforcement element of magnesium alloy, some rare earth compounds and dispersive reinforcement.
4. Thermal stability of progressive alloy mechanical functions
Rare earth elements are the most useful alloying elements of advanced magnesium alloy heat resistance, can significantly improve the high temperature strength of Mg alloy and high temperature creep resistance, the reasons for which are many: rare earth stenome coefficient in magnesium is small, can slow down the recrystallization process and progress recrystallization temperature, add aging effect and desoluble phase thermal stability, The rare earth compound with high melting point snouts the crystal boundary, prevents the misalignment of motion, and progresses the high temperature creep resistance.
5. Progressive alloy corrosion resistance
Because the melt is purified, the harmful effects of impurity iron, etc. are reduced, and then the corrosion resistance is improved.