Magnesium Alloys in Automotive Design

By Taha KhanReviewed by Lexie CornerApr 30 2024

The properties of magnesium alloys, such as their lightweight nature, high strength-to-weight ratio, and good machinability, make them highly desirable materials for the automotive industry. As manufacturers aim to enhance fuel efficiency, reduce emissions, and improve overall vehicle performance, magnesium alloys are rapidly gaining attention.¹

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Advantages of Magnesium Alloys in Automotive Applications

Magnesium is the eighth most abundant element on Earth. When alloyed with other elements like aluminum, manganese, and silicon, it transforms into a material with many unique properties, important for its application in automotive components.

The most significant advantage of magnesium alloys is their exceptionally low weight compared to other lightweight materials like aluminum. For instance, a magnesium alloy wheel design can reduce weight by 32 % compared to aluminum alloys.

Their strength-to-weight ratio enables substantial weight reduction without compromising structural integrity. This results in vehicles that are more fuel-efficient and have enhanced handling characteristics due to reduced inertia.^1,2

Automotive engineers use magnesium alloys to produce various critical vehicle components, including pedal supports, sunroofs, cylinder head covers, seat frames, body components, engine blocks, steering wheels, and transmission cases.^{1, 2}

For instance, high-pressure die-cast (HPDC) magnesium alloys like AE44 are utilized in engine cradles for weight reduction in automotive applications, as seen in the GM Chevrolet Z06 Corvette.³

Technological Innovations and Developments

Magnesium alloys offer several advantages crucial for the automotive industry; however, their corrosion susceptibility, particularly in environments with moisture and salt, has hindered their widespread usage.

Recent technological advancements are addressing this issue by implementing improved surface treatments and innovative alloy compositions that enhance the corrosion resistance of magnesium components.⁴

For instance, in a 2022 study, researchers investigated the impact of surface remelting treatment on the microstructure and corrosion resistance of AZ91 magnesium alloy. They employed gas tungsten arc welding (GTAW), using a unique two-burner system for oxide cleaning and remelting. The analysis involved electrochemical tests and hydrogen evolution rate measurements.

Results indicated significant microstructural improvements post-remelting, with refined grains and a more uniform β-Mg17Al12 phase distribution. Corrosion resistance notably increased, with remelted samples exhibiting lower corrosion current density values by up to threefold. This study highlights GTAW's efficacy as a cost-effective procedure for surface remelting, offering enhanced magnesium alloy corrosion resistance.⁴

Ongoing research into new alloy formulations continually explores new combinations of elements to create magnesium alloys with enhanced strength, ductility, and high-temperature performance. These advancements are expanding the range of applications for magnesium alloys in cars.⁵

Challenges and Limitations of Magnesium Alloys in Industry

While magnesium alloys offer numerous advantages, they also face significant challenges.

One major issue is their higher cost compared to traditional materials like steel and aluminum, which poses economic barriers to their mass production and widespread use.¹

Similarly, challenges regarding corrosion and flammability have impacted the demand for magnesium alloys, particularly in safety-critical applications. However, advancements in corrosion-resistance treatments and flame-resistant magnesium alloys have somewhat mitigated these concerns.⁶

In a recent study, researchers explored methods to enhance the flame resistance of magnesium alloys, crucial for their safe use in aviation and mechanical engineering. They compared various compositions of magnesium alloys and identified that alloys containing both the LPSO phase and Yb or Ca additives exhibited the highest flame resistance, raising ignition temperatures to 1000 °C or higher.

This study highlights the significance of the LPSO phase in increasing ignition temperatures by approximately 100 °C in the as-cast state and up to 200 °C in the heat-treated state. It also highlighted the the role of surface oxide films in protecting magnesium alloys from ignition, prompting further investigation into their formation mechanisms.

These findings will help researchers develop advanced flame-resistant magnesium alloys for diverse industrial applications, including aviation and automotive.⁶

Future Outlooks

The world is moving towards a greener future, exploring every viable option that provides environmentally friendly solutions. In this regard, the demand for fuel-efficient vehicles is growing, and magnesium alloys are expected to play a significant role in the future of automotive design. ⁷

As production costs decrease, corrosion resistance improves, and functionalities expand, magnesium alloys will likely become a more prevalent choice for car manufacturers.

The future of automotive design is increasingly linked with lighter, stronger, and more fire-resistant magnesium alloys. These materials are being considered for various applications, from engine components like cylinder blocks and transmission cases to structural parts like frames and wheels. Electric and hybrid vehicles also offer new opportunities for magnesium alloys, as weight reduction becomes even more critical.⁸

By leveraging magnesium's unique properties, such as its lightweight and high strength, automakers can optimize vehicle performance, extend driving range, and enhance overall efficiency with minimal environmental impact.

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References and Further Reading

1. Dziubinska, A., Siemionek, E., Surdacki, P., Kulisz, M., Koczurkiewicz, B. (2024). Review of Magnesium Wheel Types and Methods of Their Manufacture. Materials. doi.org/10.3390%2Fma17030584
2. Khademian, N., Peimaei, Y. (2021, August). Magnesium alloys and applications in automotive industry. [Online] ResearchGate. Available at: https://www.researchgate.net/publication/354102981_Magnesium_alloys_and_applications_in_automotive_industry
3. Fan, S., Wang, X., Wang, GG., Weiler, JP. (2023). Applications of High-Pressure Die-Casting (HPDC) Magnesium Alloys in Industry. Magnesium Alloys-Processing, Potential and Applications. doi.org/10.5772/intechopen.110494
4. Iwaszko, J., Strzelecka, M. (2022). Microstructure and Corrosion Resistance of AZ91 Magnesium Alloy after Surface Remelting Treatment. Materials. doi.org/10.3390/ma15248980
5. Liu, B., Yang, J., Zhang, X., Yang, Q., Zhang, J., Li, X. (2023). Development and application of magnesium alloy parts for automotive OEMs: A review. Journal of Magnesium and Alloys. doi.org/10.1016/j.jma.2022.12.015
6. Zasypkin, SV., Merson, DL., Brilevsky, AI., Irtegov, A. I. (2023). On selection of advanced compositions of flame resistant magnesium alloys. Letters on Materials. doi.org/10.22226/2410-3535-2023-2-104-108
7. Kulekci, MK. (2008). Magnesium and its alloys applications in automotive industry. The International Journal of Advanced Manufacturing Technology. doi.org/10.1007/s00170-007-1279-2
8. Thiagarajan, C., Lakshminarayanan, N., Anand, A., Santhosh, MN., Anderson, NJ. (2020, December). Investigation and analysis of properties of magnesium alloy for suitability to electric vehicle components. In IOP Conference Series: Materials Science and Engineering. doi.org/10.1088/1757-899X/993/1/012007

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