Magnesium alloy material and method for manufacturing the same

Abstract

The present invention provides a magnesium alloy material excellent in mechanical properties without using specific manufacturing facilities and processes and a method of manufacturing the same. The magnesium alloy material is an Mg—Zn—RE alloy containing, as an essential component, Zn and at least one of Gd, Tb, and Tm as RE, and of the rest including Mg and unavoidable impurities, and has stacking faults of a thickened two-atomic layer of Zn and RE in the alloy structure of the Mg—Zn—RE alloy. A method of manufacturing a magnesium alloy material involves a casting step, a solution treatment step, and a heat treatment step and the heat treatment step is carried out in a condition satisfying −14.58 [ln(x)]+532.32<y<−54.164 [ln(x)]+674.05 and 0<x≦2, wherein y denotes the heat treatment temperature (K) and x denotes the heat treatment time (h).

1 . A magnesium alloy material of an Mg—Zn—RE alloy containing, as an essential component, Zn and at least one of Gd, Tb, and Tm as RE, and the rest including Mg and unavoidable impurities, wherein the alloy structure of the Mg—Zn—RE alloy contains stacking faults of a thickened two-atomic layer of Zn and RE. 
   
   
       2 . The magnesium alloy material according to  claim 1 , wherein the alloy structure of the Mg—Zn—RE alloy contains recrystallized grains, the recrystallized grains have an average crystal grain diameter of 5 μm or less and a surface area ratio with respect to the alloy structure of 35% or more. 
   
   
       3 . The magnesium alloy material according to  claim 1 , wherein Zn is contained in a component range of 0.5 to 3% by atom and RE is contained in a component range of 1 to 5% by atom. 
   
   
       4 . A method for manufacturing a magnesium alloy material comprising:
 producing a cast material by casting an Mg—Zn—RE alloy containing, as an essential component, Zn and at least one of Gd, Tb, and Tm as RE, and of the rest including Mg and unavoidable impurities;   carrying out a solution treatment for the cast material; and   carrying out a heat treatment in a prescribed condition for the cast material subjected to the solution treatment,   wherein the heat treatment is carried out in a condition satisfying −14.58[ln(x)]+532.32<y<−54.164[ln(x)]+674.05 and 0<x≦2, wherein y denotes the heat treatment temperature (K) and x denotes the heat treatment time (h).   
   
   
       5 . A method for manufacturing a magnesium alloy material comprising:
 producing a cast material by casting an Mg—Zn—RE alloy containing, as an essential component, Zn and at least one of Gd, Tb, and Tm as RE, and of the rest including Mg and unavoidable impurities;   carrying out a solution treatment for the cast material;   carrying out a heat treatment in a prescribed condition for the cast material subjected to the solution treatment; and   carrying out plastic processing for the cast material subjected to the heat treatment, wherein the heat treatment step is carried out in a condition satisfying −14.58[ln(x)]+532.32<y<−54.164[ln(x)]+674.05 and 0<x≦2,   wherein y denotes the heat treatment temperature (K) and x denotes the heat treatment time (h).   
   
   
       6 . The method for manufacturing a magnesium alloy material according to  claim 5 , wherein the plastic processing is extrusion processing or forging processing.