Mg Alloys Containing Misch Metal Manufacturing Method of Wrought Mg Alloys Containing Misch Metal, and Wrought Mg Alloys Thereby

Abstract

There are provided a magnesium alloy with a misch metal, a method of producing a wrought magnesium alloy with a misch metal, and a wrought magnesium alloy produced thereby, in which a great deal of misch metal is added to magnesium, and thus refractory eutectic phases or multi-phases are formed into a stable network structure or a stable dispersed phase, thereby inhibiting deformation of a magnesium matrix at a high temperature to maintain a high strength. The magnesium alloy with the misch metal has the formula of Mg100-x-y-gAxByCz, where A is zinc (Zn) or aluminum (Al); B is the misch metal; C is at least one element selected from the group consisting of manganese (Mn), nickel (Ni), copper (Cu), tin (Sn), yttrium (Y), phosphor (P), silver (Ag), and strontium (Sr); and x, y and z are the compositions of 0 at %≦x≦6 at %, 0.8 at %≦y≦7 at %, and 0 at %≦z≦2 at %, respectively.

Description

DESCRIPTION [0001]1. Technical Field[0002]The present invention relates to a magnesium alloy with a misch metal, in which a great deal of misch metal is added to magnesium, thereby having a network structure or a dispersed phase which is stable at a high temperature and thus exhibiting excellent mechanical properties. Further, the present invention relates to a method of producing a wrought magnesium alloy which granulates solidification structures, i.e. secondary phases or multi-phases, by means of hot extrusion and hot rolling, and ultra-refines grains of a matrix, and a wrought magnesium alloy produced by the method.[0003]2. Background Art[0004]Nowadays, as environmental and saveenergy problems attract a lot of attention all over the world, it is absolutely required to make parts lighter in weight. There are stronger and stronger requests that an environmental pollution problem resulting from carbon dioxide generated during transportation by road, aviation, and rail should be sol...

AI Technical Summary

Benefits of technology

[0027]As described above, in the magnesium alloy with the misch metal according to the present invention, the misch metal is added, and thus refractory eutectic phases or multi-phases are formed into a stable network structure or a stable dispersed phase, thereby inhibiting deformation of a magnesium matrix at a high temperature. Further, other elements are additionally added, and thus precipitation / solid-solution is strengthened in a matrix structure or the network structure is strengthened, thereby having excellent mechanical properties in which a high strength is maintained at a high temperature.

[0028]Further, in the method of producing the wrought magnesium alloy according to the present invention, a secondary-phase or multiphase magnesium alloy to which the misch metal is added is recrystallized by the hot extrusion and hot rolling, and the grains are refined.

[0029]In addition, the wrought magnesium alloy with the misch metal according to the present invention has a fine grain structure, and thus exhibits mechanical properties such as a high strength and a high toughness in a room-temperature area in which the alloy is substantially used. Further, the wrought magnesium alloy has a good elongation at a temperature at which formation is substantially carried out, and thus is improved in formability.

[0030]In this manner, the magnesium alloy with the misch metal having excellent mechanical properties according to the present invention satisfies the requirements of high strength and heat resistance which are required for power transmission parts of a vehicle.

[0031]Further, by adding calcium (Ca) to the magnesium alloy with the misch metal according to the present invention, fusion in air and casting are possible, so that it is possible to promote saving of production costs.

[0032]Also, the magnesium alloy with the misch metal according to the present invention exhibits a high-temperature strength better than a heat-resistant magnesium alloy produced by existing heat treatment, so that it can be applied to parts for the vehicle and aircraft.

Problems solved by technology

In the casting magnesium alloy, because a molten metal frequently generates an eddy when passing through the gate of a metal mold to enter a cavity, its product contains a number of blowholes.

These remaining blowholes results in generating a blister on a surface of the product during heat treatment including solution heat treatment in the future, the product is not typically subjected to the heat treatment.

Hence, the AZ91 alloy has a difficulty in being applied to parts exposed to a high temperature (150° C. or more) such as a transmission case of an automobile.

However, so far, there is a limit to utility in the aspects of productivity, mechanical properties including the high-temperature creep property and corrosion resistance, and costs.

Thus, these elements have been restrictively used for the case of giving a greater weight on performance than a cost.

Meanwhile, conventionally, there is a technical problem on formation of the magnesium alloy.

For this reason, it is very difficult to form a product at a room temperature.

However, the magnesium alloy plate having a required fine grain structure is not efficiently produced using a currently commercialized magnesium alloy.

In this case, the reduction in thickness is restricted due to serious cracking, and thus the grain refinement is restricted.

In other words, this solid solution alloy is restricted in a source capable of generating recrystallization in its interior, and thus has a limit to the grain refinement.

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