Alloy member, apparatus, and method for manufacturing alloy member

Abstract

An alloy member includes a base material that includes a surface layer and is a magnesium-lithium alloy (Mg—Li alloy) having an α-phase and a β-phase, and an anticorrosive film is able to be formed on the surface layer. A degree of orientation in a (110) plane of the β-phase of the Mg—Li alloy is more than or equal to 70%. An average grain size of the Mg—Li alloy is less than or equal to 50 μm. A Li concentration of the surface layer is lower than a Li concentration of inside of the base material.

What is claimed is: 
     
         1 . An alloy member comprising:
 a base material that includes a surface layer and is a Mg—Li alloy having an α-phase and a β-phase,   wherein an anticorrosive film is able to be formed on the surface layer,   wherein a degree of orientation in a (110) plane of the β-phase of the Mg—Li alloy is more than or equal to 70 percent (%),   wherein an average grain size of the Mg—Li alloy is less than or equal to 50 micrometres (μm), and   wherein a Li concentration of the surface layer is lower than a Li concentration of an inside of the base material.   
     
     
         2 . The alloy member according to  claim 1 , wherein a thickness of the surface layer is more than or equal to 10 μm. 
     
     
         3 . The alloy member according to  claim 1 , wherein a thickness of the surface layer is more than or equal to 30 μm. 
     
     
         4 . The alloy member according to  claim 1 , wherein a crystal shape of the α-phase of the Mg—Li alloy is a needle shape. 
     
     
         5 . The alloy member according to  claim 4 , wherein an average grain size in the α-phase of the Mg—Li alloy is less than or equal to 30 μm. 
     
     
         6 . The alloy member according to  claim 1 , further comprising:
 a Li compound,   wherein after a lapse of two hours from cutting of the alloy member in a lamination direction, the Li compound is deposited from the base material.   
     
     
         7 . The alloy member according to  claim 6 , wherein the Li compound is at least one of lithium carbonate or lithium oxide. 
     
     
         8 . The alloy member according to  claim 6 , wherein a Li compound deposited from the surface layer is less than the Li compound deposited from the base material. 
     
     
         9 . The alloy member according to  claim 1 , further comprising:
 an anticorrosive film formed on the surface layer,   wherein the anticorrosive film includes an inorganic fluoride.   
     
     
         10 . The alloy member according to  claim 9 , wherein the inorganic fluoride comprises magnesium fluoride (MgF 2 ), the proportion of the magnesium fluoride (MgF 2 ) of the inorganic fluoride is more than or equal to 90% By volume. 
     
     
         11 . The alloy member according to  claim 9 , wherein a thickness of the anticorrosive film is more than or equal to 2 μm. 
     
     
         12 . The alloy member according to  claim 1 , wherein the Mg—Li alloy has a Li content of more than or equal to 5% by mass and less than or equal to 11% by mass. 
     
     
         13 . The alloy member according to  claim 1 ,
 wherein the Mg—Li alloy further contains one or more elements selected from the group consisting of aluminum (Al), zinc (Zn), manganese (Mn), silicon (Si), calcium (Ca), germanium (Ge), and beryllium (Be), and   wherein a content of a sum of the one or more elements is less than or equal to 10% by mass.   
     
     
         14 . The alloy member according to  claim 13 ,
 wherein the content of Al is less than or equal to 10% by mass,   wherein the content of Zn is less than or equal to 3% by mass,   wherein the content of Mn is less than or equal to 0.3% by mass,   wherein the content of Si is less than or equal to 0.2% by mass,   wherein the content of Ca is less than or equal to 1.0% by mass,   wherein the content of Ge is less than or equal to 1% by mass, and   wherein the content of Be is less than or equal to 3% by mass.   
     
     
         15 . The alloy member according to  claim 9 ,
 wherein a surface of the anticorrosive film on a side opposite to a surface which is in contact with the surface layer has an average surface roughness Ra of more than or equal to 0.19 μm and less than or equal to 0.9 μm and a maximum roughness Rz of less than or equal to 15 μm.   
     
     
         16 . The alloy member according to  claim 15 , wherein the anticorrosive film has a porous structure. 
     
     
         17 . An apparatus comprising:
 a housing; and   a component provided in the housing,   wherein the housing includes the alloy member according  claim 1 .   
     
     
         18 . A method for manufacturing an alloy member, comprising:
 preparing a base material that is molded using die-cast molding and is an Mg—Li alloy having an α-phase and a β-phase; and   forming a surface layer on the base material by performing an anodization process on the base material to obtain the surface layer having a Li concentration lower than a Li concentration of inside of the base material.   
     
     
         19 . The method for manufacturing the alloy member according to  claim 18 , wherein in the forming, the surface layer and an anticorrosive film on the surface layer are formed. 
     
     
         20 . The method for manufacturing the alloy member according to  claim 18 , wherein in the preparing, a molten alloy raw material is die-cast molded under application of pressure to obtain the base material of the Mg—Li alloy. 
     
     
         21 . The method for manufacturing the alloy member according to  claim 18 , wherein the forming includes
 placing a base material as a cathode and the base material of the Mg—Li alloy as an anode in a neutral ammonium fluoride aqueous solution, and   applying a voltage between the anode and the cathode.   
     
     
         22 . The method for manufacturing the alloy member according to  claim 18 , further comprising heating the base material between the preparing and the forming.