Magnesium alloy function
Melt purification
Rare earth elements can remove hydrogen, oxygen, sulfur, iron and inclusions in magnesium alloy melt to achieve the effect of degassing, refining and purifying the melt.
Melt protection
Magnesium alloy is very easy to oxidize and burn in the melting process. In industrial production, magnesium alloy is generally melted with flux covering or gas protection law, but there are many shortcomings. If the ignition temperature of magnesium alloy melt itself can be improved, direct melting of magnesium alloy in the atmosphere may be realized, which is of great significance for the further promotion and application of magnesium alloy. Rare earth is the surface active element of magnesium alloy melt, which can form a dense composite oxide film on the surface of the melt, effectively prevent the contact between the melt and the atmosphere, and greatly increase the ignition temperature of magnesium alloy melt.
Fine grain strengthening
The enrichment of rare earth elements at the front of the solid-liquid interface causes the composition to be supercooled, and a new nucleation band is formed in the undercooled zone, which leads to the formation of fine equiaxed crystals. In addition, the enrichment of rare earth elements prevents the growth of α-Mg grains and further promotes the refinement of grains. According to the Hall2Petch formula, the strength of the alloy increases with the refinement of the grain size, and compared with the body-centered cubic and face-centered cubic crystals, the grain size has a greater influence on the strength of the close-packed hexagonal metal, so the strengthening effect of the grain refinement of magnesium alloys is extremely significant.
Solution strengthening
Most rare earth elements have high solid solubility in magnesium. When rare earth elements dissolve in magnesium matrix, lattice distortion occurs due to the difference of atomic radius and elastic modulus between rare earth elements and magnesium. The resulting stress will hinder the dislocation movement, thus strengthening the magnesium matrix. The function of solid solution strengthening of rare earth elements is mainly to slow down the atomic diffusion rate, hinder the dislocation movement, strengthen the matrix, and improve the strength and high temperature creep performance of the alloy.
Dispersion strengthening
Rare earth and magnesium or other alloying elements form stable intermetallic compounds during alloy solidification. These intermetallic compounds containing rare earth generally have the characteristics of high melting point and high thermal stability, etc. They are small compound particles dispersed in and within the grain boundaries, which can nail the grain boundaries at high temperatures, inhibit the grain boundary slip, hinder the dislocation movement, and strengthen the alloy matrix.
Aging precipitation strengthening
The high solid solubility of rare earth elements in magnesium decreases with the decrease of temperature. When the single-phase solid solution at high temperature is cooled rapidly, an unstable susaturated solid solution is formed. After a long time of aging, a fine and dispersed precipitate phase is formed. The interaction between the precipitated phase and the dislocation increases the strength of the alloy.
Application of rare earth magnesium alloy
The rare earth magnesium alloy has the characteristics of high temperature resistance and high strength. Due to the high cost of alloy after the addition of rare earth elements, rare earth magnesium alloy was mainly used in aerospace, missiles and other military fields, but with the development of social and economic, military and civilian fields have been greatly expanded.
Hot Tags: magnesium alloys, China magnesium alloys manufacturers, suppliers, factory, rare earth Mg alloy, Mg alloy, Rare Earth Magnesium Alloy, Magnesium rare earth, Magnesium Alloys, Containing Magnesium Alloy
