Aluminum and blue tungsten are two very different metals used for different purposes. Aluminum is a soft, lightweight, and very common metal while blue tungsten is a dense, hard metal used to make filaments for light bulbs and other specialized applications. Blue tungsten would not be well suited for most aluminum applications, but there are a few key factors to consider.
The Properties of Aluminum and Blue Tungsten
Aluminum is known for being lightweight, corrosion resistant, electrically and thermally conductive, and easy to machine and form. It has a density of around 2.7 g/cm3 and a melting point of 660°C. Some of the most common uses of aluminum include aircraft manufacture, building and construction, packaging, and consumer products.
Blue tungsten, also known as osmium tungsten or osram tungsten, has very different properties from aluminum. It has a density of 18-19 g/cm3, more than 6 times higher than aluminum. It also has a very high melting point of around 3400°C. Blue tungsten is brittle and hard to machine. Because of its high density, it is used when high mass in a small volume is needed. Some uses include tungsten heavy alloy counterweights and radiation shielding.
|Melting Point (°C)||660||3400|
Using Blue Tungsten for Aluminum Applications
Based on their vastly different properties, blue tungsten would likely not be a good substitute for aluminum in most applications. Here are a few key factors to consider:
- Weight – The high density of blue tungsten makes it unsuitable for lightweight applications where low density aluminum would normally be used.
- Machining – Aluminum is easy to cut, bend, extrude, and otherwise form. Blue tungsten’s brittleness and hardness make it extremely difficult to machine.
- Corrosion Resistance – Aluminum forms a protective oxide layer and resists corrosion very well. Blue tungsten has poor corrosion resistance.
- Conductivity – Aluminum is used where good electrical and thermal conductivity are needed. Blue tungsten has much lower conductivity.
- Cost – Commodity metals like aluminum are far less expensive than rare metals like blue tungsten.
For most structural, packaging, electrical, or other common aluminum applications, blue tungsten just does not have the right mix of properties needed. The heavyweight but brittle tungsten would compromise the functionality of aluminum in most cases.
When Blue Tungsten Could Work
While it may not be suitable as a wholesale replacement for aluminum, there are a few specialized applications where blue tungsten could potentially be used:
- Counterweights – When extremely high density is needed in a small volume, blue tungsten could be a good substitute for lead or steel counterweights.
- Radiation shielding – The density of blue tungsten helps block radiation penetration, making it suitable for shielding in medical and nuclear applications.
- Vibration damping – Blue tungsten’s high mass helps damp vibrations in high precision instruments or other sensitive applications.
- Ballast – In situations where mobile ballast is needed, like in the keel of a boat, blue tungsten counterweights could provide high mass.
However, even in these cases other metals like lead, steel, or specialty tungsten alloys will usually be a lower cost and more practical choice. The applications where blue tungsten offers unique advantages over other materials are limited.
Joining Blue Tungsten to Aluminum
In some special cases it may be desirable to join blue tungsten parts to aluminum. Because of their vastly different melting points and coefficients of thermal expansion, conventional welding is not an option. Brazing or soldering using specialty high temperature braze alloys is one option. Reactive or refractory metal brazes can create strong joints between dissimilar metals.
Adhesive bonding may also be possible. High strength epoxy adhesives are available that can form robust bonds between metals with poor weldability. The adhesive joint design would need to compensate for thermal stresses from the mismatched expansion behavior. Good surface preparation and priming would be essential.
Mechanical fastening methods like bolting or riveting could also be used to join blue tungsten and aluminum. The joint would need to be engineered to handle the materials’ differences but this is a simple and accessible joining method. In each case, joint design, testing, and inspection would be critical.
In summary, blue tungsten is generally not suited as a substitution for aluminum due to its much higher density, poor machinability and corrosion resistance, high cost, and other disparities with aluminum’s properties. Only in applications specifically benefiting from blue tungsten’s extreme density could it potentially outperform aluminum. With care taken in the joining method, it is possible to mechanically or adhesively bond blue tungsten to aluminum in specialized applications requiring both metals’ unique attributes.