The Best Aluminum Alloys for Extruded Heat Sinks

The efficiency and performance of a heat sink depend on several factors. One needs to maintain a perfect balance between these factors that include:

1. Thermal conductivity of Material used

2. Air velocity

3. Protrusion design

4. Surface treatment.

Aluminum and copper are the most commonly used materials in heat sinks as they have well defined thermal properties. However, Aluminum is the preferred material due to several reasons.

Advantages of using Aluminum over Copper in Heat Sinks

While copper has higher thermal conductivity (approximately 60% higher than aluminum), its main drawback is its lack of versatility, high density and high cost. Aluminum scores over Copper, as it’s lightweight, extremely versatile and relatively lower in cost. Moreover, aluminum has good conductivity and can be extruded while copper heat sinks have to be machined and skived. Thus, Aluminum is the material of choice for heat sinks and extrusion is the most common manufacturing process. Custom aluminum extrusions are ideal for most applications and the material of choice for heat sinks owing to their affordability and versatility.

Choosing the Best Aluminum Alloy for Heat Sinks

While one would think that the alloy with the highest thermal conductivity should be used for heat sinks, we must consider its durability. The temper of the alloy used is also an important consideration. The Aluminum alloy 1050A has a higher thermal conductivity of 229 W/m•K, but it is too soft mechanically to be used for heat sinks. One should opt for aluminum alloys in the 6000 series as they are strong, malleable, and are ideal for extrusion. Out of these, the Alloys 6060, 6061 and 6063 series are the most preferred for designing heat sinks. The following table will give us a better idea of the thermal conductivity of different aluminum alloys:

The Ideal Aluminum Alloy for Your Project

As the thermal conductivity between 6000 series alloys is relatively minimal, one can make an informed choice by maximizing the surface area of the heat sink and optimizing airflow. One should make sure that the heat sink conforms to the hot component and leave the tiniest possible gap. While 6063 is versatile and cost-effective, 6061 has higher tensile strength, up to 240 MPa. (Tensile strength of 6063 is up to 186 MPa). 6061 Alloy (with magnesium and silicon) is a precipitation-hardening alloy with excellent mechanical properties and weld-ability.

Make the Right Choice of Custom Aluminum Extrusions with OD Metals

As the trusted leaders in Aluminum extrusions, with decades of industry experience, OD metals is the best technical resource partner for your industrial needs. Trust the experts for making the right choice of aluminum alloys for your heat skinks and heat transfer applications. We will ensure the ideal alloy for your application at just the right price!

Call us today at 1 (855) .272.3889 or email: sales@odmetals.com