Next-Level Thermal Management with Rheocasting

Powerful electronics depend on cooling systems to effectively manage high thermal loads. Yet, traditional manufacturing approaches for heat sinks struggle to deliver the required conductivity.

The limiting Factors of HPDC Alloys

In many cases, high-pressure die-casting with their high-silicon alloys results in decent castability but comparatively poor thermal properties. Silicon atoms and the dendritic microstructure of liquid HPDC inhibit the free flow of electrons, lowering thermal conductivity to levels around 140 W/mK or less. That is rarely sufficient for demanding applications like 5G antenna systems, which generate substantial heat and need every watt of conduction possible to prevent overheating.

When a heat sink fails to remove heat efficiently, the electronics lose performance or shut down altogether. In the case of the 5G antenna, poor thermal conductivity costs in the transmittable range. This loss of range makes the network way more expensive than it should be. Moreover, a large active cooling fan might mitigate some issues. Still, it adds both complexity and cost while risking unwanted nesting by wildlife.

Cutting a heat sink from a block of pure aluminium certainly maximizes conductivity, but the process is expensive and time-consuming, and pure aluminium lacks the strength often required in complex electronic housings.

Casting remains the most logical route for producing detailed fins and functional mounting points. However, standard HPDC alloys with seven to twelve percent silicon inherently limit the conductivity because every foreign atom, phase boundary, and porosity channel disrupts electron movement. No matter how well-designed, HPDC processes still introduce turbulence and dendrites that hinder conduction.

Heat Sinks in Rheocasting

That compromise no longer needs to hold us back. Rheocasting, with its semi-solid slurry, solves these challenges. It breaks the regular dendritic growth and forms rounded globulites instead. These globulites provide a pathway for superior electron flow, and the laminar filling phase helps ensure a pore-free casting.

One critical factor is alloy selection. With Rheocasting, designers are no longer bound to high-silicon content. Alloys with as little as 1.7 percent silicon become feasible to cast, opening up the potential for conductivity numbers in the 170–190 W/mK range, all the way up to around 198 W/mK, depending on the exact chemistry. That is very close to the 220–225 W/mK upper limit of pure aluminium without having to mill a complete part from a large block, and it comes with sufficient mechanical properties to withstand real-world loads.

A 100 percent post-consumer scrap alloy can be used, dramatically reducing the carbon footprint while retaining these excellent thermal characteristics. One telecom OEM has already taken advantage of this combination through the “Rheocool” solution, switching from a traditional HPDC approach to Rheocasting in order to improve the power output and range of its 5G antennas. Rheocasting provides the geometry flexibility demanded by modern electronics yet delivers conductivity levels that ensure significant heat removal even under punishing conditions.

Expanding beyond the telecom sector, any industry requiring powerful electronics needs robust heat management solutions, whether for electric vehicle power electronics, data center servers, or industrial control units. Many of these products cannot afford the risk of partial failure due to high heat, and repair downtime can be staggeringly expensive. By pairing Rheocasting with an optimally lean chemical composition, foundries can achieve high thermal conductivity, eliminate fans or reduce their size, ensure corrosion resistance, and maintain leak-tight castings that protect sensitive circuitry from moisture.

What will the next Series Production Application be?

High-silicon HPDC solutions cannot reliably match those properties, nor can milling pure aluminium at scale cost-effectively. Rheocasting is now the proven option for large-scale production of complex, highly efficient heat sinks, allowing the electronics industry to push performance boundaries without risking downtime from heat-related failures.

Anyone looking to extend the capability of standard HPDC lines while staying ahead of rising performance demands and sustainability goals should consider adopting Rheocasting for their thermal management components. You find more information in the Rheocasting Expert on Demand Package or directly schedule a free Consultation Call down below.