What are the properties of AlSiC material?

Aluminum-based silicon carbide (AlSiC) is driving changes in new energy vehicles and aerospace with its innovative properties, boasting thermal conductivity 10 times greater than traditional alloys and 50% weight reduction. Its thermal expansion coefficient precisely matches that of chips, ensuring intact solder joints through 10,000 thermal cycles and doubling the lifespan of IGBT modules. The global automotive brake disc market is expected to exceed 404.6 billion yuan by 2031. Driven by the trend of lightweighting, this material, with a specific stiffness three times that of aluminum, is reshaping the boundaries of precision manufacturing for applications ranging from electronic packaging to satellite brackets and brake discs.

Aluminum silicon carbide (AlSiC) is a high-performance material composed of an aluminum matrix reinforced with silicon carbide particles. Its unique physical and mechanical properties have led to its widespread application in electronic packaging, aerospace, and new energy vehicles. However, its high hardness and wear resistance also significantly increase its processing difficulty, requiring particular attention to process parameters and equipment selection when machining with milling machines. The following analysis focuses on both material properties and processing considerations.

AlSiC boasts a thermal conductivity of 180–240 W/mK, approximately 10 times that of conventional Kovar alloys. This effectively dissipates heat and prevents thermal failure in electronic devices. Furthermore, its thermal expansion coefficient (6.5–9.5×10⁻⁶/K) can be adjusted to match that of semiconductor chips by adjusting the silicon carbide content, reducing fatigue cracking caused by thermal stress. While its density is comparable to aluminum (approximately 3.0 g/cm³), its specific stiffness (stiffness/density) is three times that of aluminum and 25 times that of copper. This makes AlSiC particularly suitable for weight-sensitive aerospace structures, such as satellite mounts and engine components.

The addition of SiC particles significantly enhances the material’s hardness and wear resistance (HV ≥ 2500), enabling stable operation in high-temperature and highly corrosive environments, such as automotive brake discs and turbine blades. Its isotropic physical and mechanical properties make it less susceptible to deformation caused by uneven stress distribution after machining, making it suitable for the precision machining of complex structural parts.

AlSiC’s thermal conductivity (170240 W/mK) is 10 times that of traditional Kovar alloys, and its thermal expansion coefficient (6.59.5×10⁻⁶/K) matches chips and ceramic substrates, preventing thermal stress failure. For example, the AlSiC baseplate in an IGBT module can maintain an intact solder layer after tens of thousands of thermal cycles, significantly improving device reliability. Typical applications include IGBT heat sinks for new energy vehicles, LED packaging lighting substrates, and microwave integrated circuit packaging.

AlSiC’s electrical conductivity can be optimized by adjusting its composition, making it suitable for high-frequency signal transmission line design, improving signal stability and transmission efficiency. In the aerospace and military sectors, lightweight structures are used in satellite reflectors, aircraft fuselage frames, and other applications, achieving significant weight reductions. For example, replacing Kovar alloy with AlSiC can reduce weight by up to two-thirds.

In the automotive industry and new energy sectors, AlSiC is used in engine blocks, pistons, brake discs, and other applications, reducing weight by 50% compared to cast iron brake discs, thereby increasing the range of new energy vehicles. For example, aluminum-based brake discs reinforced with silicon carbide particles can reduce energy consumption and improve braking stability in electric vehicles. The global automotive AlSiC brake disc market is projected to reach US$4,046.43 million by 2031, with a compound annual growth rate of 218.04%.

Aluminum-based silicon carbide, thanks to its comprehensive performance, has become a core material in high-end manufacturing, with its application continuing to expand in industries such as electronics, aerospace, and automotive. With the optimization of preparation processes and the widespread availability of specialized processing equipment, its application potential will be further unleashed.

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