Method of manufacturing magnesium alloy products

Abstract

A method of manufacturing products, which have complex and accurate shape and exhibit high reliability of properties and enough corrosion resistance, at sufficiently high yield by employing a combination of casting and forging for forming magnesium alloy of which composition allows casting and which is excellent in forgeability. A magnesium alloy containing 2-10 mass % aluminum is cast to have crystal grain size not greater than 30 μm. After the cast semifinished product is subjected to solution treatment, the semifinished product is forged to have crystal grain size not greater than 10 μm and is then further forged to have a desired shape. A magnesium alloy containing 2-10 mass % aluminum is cast to have crystal grain size not greater than 10 μm and the cast semifinished product is forged after solution treatment.

What is claimed is:  
     
         1 . A method of manufacturing magnesium alloy products comprising the steps of: 
 casting a magnesium alloy containing 2-10 mass percent aluminum to obtain a cast semifinished product having crystal grain size not greater than 30 μm;    subjecting the cast semifinished product to solution treatment at a temperature between the solid solution temperature and the solidus curve of the composition of the alloy,    after solution treatment, forging the cast semifinished product to have a forged semifinished product having crystal grain size not greater than 10 μm, and    further forging the forged semifinished product to have a desired shape.    
     
     
         2 . A method of manufacturing magnesium alloy products as claimed in  claim 1 , wherein the aluminum content of the magnesium alloy is in a range from 2.5 to 6 mass percent.  
     
     
         3 . A method of manufacturing magnesium alloy products as claimed in  claim 1 , wherein the casting is conducted using a die casting method or the thixo molding method.  
     
     
         4 . A method of manufacturing magnesium alloy products as claimed in  claim 1 , wherein the solution treatment is conducted at a temperature between 380 and 440° C. for 1 to 24 hours.  
     
     
         5 . A method of manufacturing magnesium alloy products as claimed in  claim 1 , wherein the forging is conducted under conditions of strain rate and temperature selected to have a Z value in a range from 10 9  to 10 13 .  
     
     
         6 . A method of manufacturing magnesium alloy products as claimed in  claim 5 , wherein the crystal grain-refined forged semifinished product has a crystal grain size not greater than 10 μm.  
     
     
         7 . A method of manufacturing magnesium alloy products as claimed in  1 , wherein the crystal grain-refined forged semifinished product is forged under conditions of a strain rate and temperature selected to have a Z value of 10 13  or less.  
     
     
         8 . A method of manufacturing magnesium alloy products comprising steps of: 
 casting a magnesium alloy containing 2-10 mass aluminum to obtain a cast semifinished product having crystal grain size not greater than 10 μm,    subjecting the cast semifinished product to solution treatment at a temperature between the solid solution temperature and the solidus curve of the composition of the alloy, and    after solution treatment, forging the semifinished product to have a desired shape.    
     
     
         9 . A method of manufacturing magnesium alloy products as claimed in  claim 8 , wherein the aluminum content of the magnesium alloy is in a range from 2 to 6 mass.  
     
     
         10 . A method of manufacturing magnesium alloy products as claimed in  claim 8 , wherein casting is conducted in a die casting method.  
     
     
         11 . A method of manufacturing magnesium alloy products as claimed in claims  8 , wherein the solution treatment is conducted at a temperature between 380 and 440° C. for 1 to 24 hours.  
     
     
         12 . A method of manufacturing magnesium alloy products as claimed in  8 , wherein the forging is conducted under conditions of strain rate and temperature selected to have a Z value lower than 10 13 .