Magnesium casting technology for structural applications

- Core Objective of the Research: To provide a comprehensive overview of magnesium alloy melting and casting processes, examine the historical development, current status, and potential applications of structural magnesium castings, primarily focusing on the automotive industry, and discuss associated technological challenges. The increasing global demand for energy, environmental protection initiatives, and government regulations are expected to drive the adoption of lightweight magnesium castings in the coming decades.

- Main Methodology: The study employs a literature review and analysis of magnesium alloy melting and casting processes. It examines the historical development of magnesium casting technology, current casting techniques, structural applications in automotive, aerospace, and power tool industries, and assesses the opportunities and challenges associated with using magnesium alloys for structural applications.

- Key Results: The research provides a detailed overview of various magnesium casting processes, including high-pressure die casting (HPDC), low-pressure die casting (LPC), vacuum-assisted HPDC, super-vacuum die casting (SVDC), squeeze casting, lost foam casting, ablation casting, and semi-solid casting. It offers an in-depth analysis of magnesium's use in structural applications, particularly in the automotive sector, highlighting the advantages of magnesium alloys (excellent castability, lightweight nature) and the challenges (porosity, corrosion susceptibility, fatigue strength). Alternative casting processes, like vacuum die casting and super-vacuum die casting, are presented as potential solutions to address porosity issues. The development and application of Integrated Computational Materials Engineering (ICME) tools are anticipated to accelerate the adoption of magnesium castings in structural applications.

Researcher Information

  • Affiliation: The paper does not explicitly state the author's specific affiliation beyond what is shown in the paper itself.
  • Author: Alan A. Luo
  • Main Research Area: Magnesium casting technology

Research Background and Objectives

  • Industrial Context: Growing demand for lightweight materials across various sectors, including automotive, aerospace, and power tools.
  • Specific Technological Challenges: Magnesium's inherent challenges in casting (high porosity, susceptibility to oxidation and burning), and the need for environmentally friendly alternatives to traditional protective gases (e.g., SF6). Also noted are the issues of corrosion resistance, fatigue strength, and crashworthiness.
  • Research Goals: To comprehensively review magnesium alloy melting and casting processes, analyze the historical development and current trends in structural magnesium casting (with automotive applications as a key focus), identify and address technical challenges, and offer insights into future prospects for magnesium alloys in structural applications.

Main Objectives and Research Content of the Paper

  • Main Objectives: To provide a complete overview of magnesium alloy casting technologies, analyze the challenges and opportunities associated with their application in structural components (especially within the automotive industry), and to provide future directions for research and development.
  • Problems Addressed: The research directly addresses the challenges of porosity, corrosion resistance, and fatigue strength inherent in magnesium castings. It also notes the environmental concerns related to traditional casting processes.
  • Stepwise Approach to Problem Solving: The paper systematically addresses the challenges by:
    1. Providing a detailed overview of existing magnesium casting methods, including their specific characteristics, advantages, and limitations.
    2. Thoroughly analyzing the historical development of magnesium castings in major industrial sectors, primarily focusing on automotive applications.
    3. Examining current applications of magnesium castings in various industries, especially those in the automotive sector.
    4. Identifying and discussing the key technological challenges associated with wider adoption of magnesium castings, focusing on porosity, corrosion, and fatigue performance.
    5. Proposing and explaining alternative casting methods (vacuum die casting, super-vacuum die casting, squeeze casting) as potential solutions to address the aforementioned limitations.
    6. Discussing the role of ICME tools in accelerating the adoption of magnesium castings in structural applications.
  • Key Figures (Refer to the figure captions/alt text within the original paper for detailed descriptions): The paper includes numerous figures illustrating various aspects of magnesium casting processes, equipment, and resulting components. These figures are crucial for understanding the processes and results discussed.
Fig. 1. Cross section of a stationary fuel-fired furnace used for the open crucible melting of magnesium alloys [2].
Fig. 1. Cross section of a stationary fuel-fired furnace used for the open crucible melting of magnesium alloys [2].
Fig. 2. (a) Modern electrical furnace with a steel cover; and (b) metal transfer tube delivering molten magnesium to a die casting machine (Courtesy of Metamag, Inc., Strathroy, ON, Canada).
Fig. 2. (a) Modern electrical furnace with a steel cover; and (b) metal transfer tube delivering molten magnesium to a die casting machine (Courtesy of Metamag, Inc., Strathroy, ON, Canada).
Fig. 3. Schematics of hot chamber die casting [8].
Fig. 3. Schematics of hot chamber die casting [8].
Fig. 4. Typical magnesium parts made by hot chamber die casting process (Courtesy of Contech US, LLC and Foxconn Technology Group, China).
Fig. 4. Typical magnesium parts made by hot chamber die casting process (Courtesy of Contech US, LLC and Foxconn Technology Group, China).
Fig. 5. Schematics of cold chamber die casting [8].
Fig. 5. Schematics of cold chamber die casting [8].
Fig. 6. General Motors magnesium instrument panel beams made by cold chamber die casting.
Fig. 6. General Motors magnesium instrument panel beams made by cold chamber die casting.
Fig. 7. Gibbs vertical vacuum assisted die casting process (Courtesy of Gibbs Die Casting, Henderson, KY, USA [11]).
Fig. 7. Gibbs vertical vacuum assisted die casting process (Courtesy of Gibbs Die Casting, Henderson, KY, USA [11]).
Fig. 8. A schematic diagram of a typical low pressure casting machine [17].
Fig. 8. A schematic diagram of a typical low pressure casting machine [17].
Fig. 9. A prototype magnesium control arm made by GM using low pressure die casting process.
Fig. 9. A prototype magnesium control arm made by GM using low pressure die casting process.
Fig. 10. A schematic diagram of a Thixomolding machine [21].
Fig. 10. A schematic diagram of a Thixomolding machine [21].
Fig. 11. Schematic illustrating direct squeeze casting process operations: (a) melt into die cavity; (b) close tooling, solidify melt under pressure; and (c) eject casting [8].
Fig. 11. Schematic illustrating direct squeeze casting process operations: (a) melt into die cavity; (b) close tooling, solidify melt under pressure; and (c) eject casting [8].
Fig. 12. Schematic illustrating metal flow in (a) conventional die casting; and (b) indirect squeeze casting process [8].
Fig. 12. Schematic illustrating metal flow in (a) conventional die casting; and (b) indirect squeeze casting process [8].
Fig. 13. Ablation casting process for aluminum and magnesium casting [26].
Fig. 13. Ablation casting process for aluminum and magnesium casting [26].
Fig. 14. Pratt & Whitney F119 auxiliary casing in ELEKTRON WE43 alloy [37].
Fig. 14. Pratt & Whitney F119 auxiliary casing in ELEKTRON WE43 alloy [37].
Fig. 15. Rolls Royce tray in ELEKTRON ZRE1 alloy [37].
Fig. 15. Rolls Royce tray in ELEKTRON ZRE1 alloy [37].
Fig. 16. HPDC magnesium casting Lincoln MKT liftgate inner (photo courtesy of Meridian Lightweight Technologies) [49].
Fig. 16. HPDC magnesium casting Lincoln MKT liftgate inner (photo courtesy of Meridian Lightweight Technologies) [49].
Fig. 17. LPDC magnesium alloy wheel for Chevrolet Corvette.
Fig. 17. LPDC magnesium alloy wheel for Chevrolet Corvette.
Fig. 18. The BMW composite engine block showing a cutaway of the magnesium exterior revealing the aluminum interior [35].
Fig. 18. The BMW composite engine block showing a cutaway of the magnesium exterior revealing the aluminum interior [35].
Fig. 19. Magnesium powertrain components from the USCAR magnesium powertrain cast components project; (a) LPDC cylinder block, (b) Thixomolded front engine cover, (c) HPDC oil pan and (d) HPDC rear seal carrier [54].
Fig. 19. Magnesium powertrain components from the USCAR magnesium powertrain cast components project; (a) LPDC cylinder block, (b) Thixomolded front engine cover, (c) HPDC oil pan and (d) HPDC rear seal carrier [54].
Fig. 20. Aluminum isolator locations for Chevrolet Corvette Z06 magnesium cradle (bottom & top views) [50].
Fig. 20. Aluminum isolator locations for Chevrolet Corvette Z06 magnesium cradle (bottom & top views) [50].
Fig. 21. USCAR demo structure build using (a) FSLW (friction stir linear welding); and (b) LSPR (laser-assisted self-pierce rivet) joining processes [67].
Fig. 21. USCAR demo structure build using (a) FSLW (friction stir linear welding); and (b) LSPR (laser-assisted self-pierce rivet) joining processes [67].
Fig. 22. Integrated Computational Materials Engineering (ICME) framework for magnesium applications.
Fig. 22. Integrated Computational Materials Engineering (ICME) framework for magnesium applications.

Results and Achievements

  • Quantitative Results: The paper presents numerous quantitative data points, including dimensional tolerances, minimum wall thicknesses, casting/molding cycle times, die life, and tensile properties (yield strength, ultimate tensile strength, elongation) for different magnesium alloys and casting processes. These values are reported in Tables 1, 3, 4, and 5.
  • Qualitative Results: The paper offers a thorough qualitative analysis of the historical development of magnesium castings, their current and potential applications in various industries (automotive, aerospace, power tools), the technological challenges associated with their use, and potential solutions to overcome these challenges.
  • Technological Achievements: The paper highlights advancements in magnesium casting technology, including the development of vacuum die casting, super-vacuum die casting, and squeeze casting methods to mitigate porosity issues. It also discusses advancements in alloys that address corrosion resistance and improved mechanical properties. The integration of ICME tools is presented as a significant step towards accelerating the adoption of magnesium castings.

Copyright and References

This document summarizes Alan A. Luo's paper "Magnesium casting technology for structural applications".
Paper Source: https://doi.org/10.1016/j.jma.2013.02.002
This document is a summary and is not intended for commercial use without permission.

References

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Tags: aluminum alloy; ,AZ91D; ,CAD; ,Casting Technique; ,Die casting; ,Die Casting Congress; ,High pressure die casting; ,Magnesium alloys; ,Microstructure; ,Permanent mold casting; ,자동차 산업; ,주조 기술