I. Common Magnesium Alloy Grades for Plastic Deformation Processing

Based on their primary alloying elements, magnesium alloys can be classified into the following systems:

• Mg–Al series (Mg–Al–Zn)

• Mg–Zn series

• Mg–Mn series

• Mg–Rare Earth (Mg–RE) series

• Mg–Li series

  Common magnesium alloy grades used for plastic deformation include:

  AZ31B, AZ40, AZ61, AZ63B, AZ80, M1C, ME20M, ZK60, ZK61, WE43, WE54, VW84M, and LA103.
  Role of Major Alloying Elements
  Aluminum (Al)

  Aluminum is one of the most widely used alloying elements in magnesium alloys. Its maximum solid solubility in magnesium is approximately 12.7%, forming the intermetallic phase Mg17Al12. Aluminum significantly improves mechanical strength, corrosion resistance, castability, fluidity, ductility, and toughness. However, excessive aluminum content increases stress corrosion susceptibility and brittleness.
   

  Zinc (Zn)
   

  Zinc has a maximum solid solubility of 6.2% in magnesium. It enhances mechanical strength, corrosion resistance, and fluidity, and provides both solid-solution strengthening and precipitation hardening effects. However, Zn contents above 1% may lead to hot shortness at elevated temperatures. Zinc is also commonly combined with zirconium or rare earth elements to form high-strength precipitation-hardened magnesium alloys.

  Manganese (Mn)
  Manganese primarily improves the corrosion resistance of magnesium alloys. Mg–Mn alloys exhibit excellent corrosion performance. Mn also removes iron and other heavy metal impurities, preventing the formation of harmful intermetallic compounds and significantly improving the seawater corrosion resistance of Mg–Al and Mg–Al–Zn alloys.
  Tin (Sn) and Silver (Ag)
  The addition of tin improves ductility and reduces the tendency for hot cracking during thermal processing. Silver has a maximum solubility of 15.5% in magnesium and provides solid- solution strengthening while enhancing aging response, thereby improving high-temperature strength and creep resistance.
  Zirconium (Zr)
  Zirconium is a powerful grain refiner in magnesium alloys, improving casting quality and enhancing formability during plastic deformation.
  Iron (Fe), Copper (Cu), and Nickel (Ni)
  Iron is a critical impurity element that significantly degrades corrosion resistance, even at trace levels. Copper contents above 0.05% and small amounts of nickel also severely reduce corrosion resistance, although they may improve high-temperature strength. For corrosion-sensitive

  applications, nickel content must be controlled below 0.005%. 3/9

  Lithium (Li)

  Lithium has high solubility in magnesium and provides solid-solution strengthening while significantly reducing alloy density. It improves ductility but reduces strength and corrosion resistance.
  Calcium (Ca)

  Calcium has limited solubility in magnesium and forms the Mg2Ca phase. Small additions reduce oxidation during melting and heat treatment, refine grain structure, improve creep resistance, and increase ignition temperature.
  Rare Earth Elements (RE)

  Rare earth elements diffuse slowly in magnesium and form fine, stable dispersed phases. Mg– RE alloys exhibit strong solid-solution and precipitation strengthening effects, resulting in improved room-temperature strength, high-temperature strength, and creep resistance.
  
   

  I. Extrusion Processing of Magnesium Alloys

  Extrusion is a pressure-forming process in which a heated billet is forced through a die to obtain the desired cross-sectional shape. Based on machine configuration, extrusion presses can be classified as horizontal or vertical.
  
  

   

  Horizontal Extrusion Presses

  In horizontal extrusion presses, the main movement direction is parallel to the ground. Key components include the container, die, and ram. After billet loading, pressure is applied through the ram, forcing the magnesium alloy through the die to form the required profile.

  Vertical Extrusion Presses
  
  

   

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  Vertical extrusion presses feature movement and extrusion directions perpendicular to the ground. They occupy less floor space but require deeper foundations. Vertical presses offer advantages such as low wear, uniform thermal deformation, excellent dimensional stability, and minimal tube eccentricity, making them especially suitable for producing tubes and hollow profiles.

  Extrusion Methods

  Based on material flow direction, extrusion processes include:

  • Direct (Forward) Extrusion

  • Indirect (Backward) Extrusion

  • Combined Extrusion

    In direct extrusion, the metal flows in the same direction as the applied pressure, resulting in significant friction between the billet and container. This process is widely used due to strong equipment adaptability and stable surface quality. Typical magnesium alloy extrusion temperatures range from 300°C to 450°C.

    In indirect extrusion, the billet remains stationary relative to the container, eliminating friction and significantly reducing extrusion force. This method enables higher extrusion ratios at lower temperatures and provides uniform microstructure and mechanical properties, higher material yield, and reduced scrap.

    III. Extruded Magnesium Alloy Profiles and Applications
    Extruded magnesium alloy products include solid profiles and hollow profiles. Hollow profiles require complex die designs with flow channels and welding chambers to rejoin metal streams under high temperature and pressure.

   

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  In addition to conventional extrusion methods, research has reported advanced techniques such as asymmetric extrusion, rotary backward extrusion, cyclic extrusion, secondary extrusion, and composite billet extrusion. Extrusion can also be combined with other processes, including extrusion + forging, extrusion + drawing, and extrusion + rolling.Typical Applications

  Sacrificial Anodes

  Extruded magnesium sacrificial anodes are currently one of the most widely used magnesium extrusion products. Common alloy grades include AZ31B, M1C, and AZ63B, supplied in round and rectangular bars.
  Rail Transportation

  Magnesium alloy extrusions play a key role in rail vehicle lightweighting, reducing vibration, noise, and energy consumption while increasing payload capacity. Large cross-section, ultra- long, high-precision magnesium alloy profiles have been successfully applied in high-speed trains, including sidewall panels, luggage racks, floor guide rails, beams, and longitudinal members.

  Textile Machinery

  
  
   

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  Large hollow magnesium alloy profiles are used in warp knitting machines and needle beds, significantly reducing inertia and improving operational stability during high-speed operation.

  Aerospace and Defense
  In aerospace and military applications, magnesium alloy extrusions leverage their lightweight advantages and electromagnetic shielding performance.

  IV. Current Challenges in Magnesium Alloy Extrusion 1. Cost Reduction

  Although billet costs can approach those of aluminum at scale, magnesium alloys typically require lower extrusion speeds to avoid cracking, resulting in higher production
  
  

   

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  costs. Developing high-speed extrudable magnesium alloys is essential for cost

  reduction.
  2. High Strength at High Productivity

  Many magnesium alloy profiles currently match the strength levels of 6061 and 6063 aluminum alloys, with some reaching tensile strengths close to 500 MPa. However, productivity and formability still lag behind aluminum alloys. Ongoing research aims to develop high-strength magnesium alloys suitable for high-speed extrusion, enabling broader industrial adoption.

  About the Technical Support
  This article is provided by Hilbo Magnesium alloy Material co.,Ltd, a manufacturer and global supplier of magnesium alloy materials, including magnesium alloy sheets, plates, tubes, bars, and extruded profiles...etc.
  If you have technical questions regarding magnesium alloy extrusion, material selection, or application design, please feel free to contact our technical team:

  Email: scm@hilbo-mg.com