Page 23 - Australian Defence Magazine March-April 2022

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or with the optimal but slightly more expensive solution?” What Titomic and Boeing are investigating is a grade of titanium which, because of its sustainable life cycle and
production efficiencies, counters this challenge.
There are a number of factors which give green titanium its ‘green’ prefix – sustainable raw materials, a more sus- tainable conversion process, a more sustainable part manu- facturing process thanks to TKF technology, and finally a
longer-lasting lightweight product.
The TKF process involves introducing a metal powder
into a gas stream and accelerating it onto a substrate or a scaffold at supersonic speeds. Upon impact, the particles fuse to the surface and to each other, which on layer- ing, build up into near-net-shape metal components. The method is faster and more powerful than any other additive manufacturing technology, capable of rapidly manufactur- ing parts up to 9m x 6m x 1.5m in size.
The traditional powder used by conventional metal additive manu- facturing methods (e.g., LPBF) is a more highly refined ‘spherical pow- der’. With spherical powder, all par- ticles are a similar size and shape. This allows the powder to flow like a liquid and uniformly melt with a high-powered laser beam. However, metal powder does not naturally have a spherical structure and this needs to be created using energy-intensive and expensive atomisation processes.
“THERE IS ALWAYS A TRADE-OFF IN INDUSTRIAL MANUFACTURING; DO I MAKE DO WITH THE LESS OPTIMAL BUT CHEAPER SOLUTION, OR WITH THE OPTIMAL BUT SLIGHTLY MORE EXPENSIVE SOLUTION?”
WHY GREEN TITANIUM?
Titanium’s high strength-to-density ratio, excellent corrosion resistance and sustainable processing and production prop- erties make it a favoured material in engineering. Its high cost, however, means it is not as accessible as other metals.
“Titanium has phenomenal mechanical attributes that nobody is disputing,” Koeck explained. “The only problem you’re always facing with titanium is that it’s expensive. So, in many use cases around the globe, steel is used rather than titanium – not because steel is better, but because it is relatively cheap.
“There is always a trade-off in industrial manufacturing; do I make do with the less optimal but cheaper solution,
In contrast, a larger variation in
the size and shape of particles does
not matter in the TKF process, as there is no need to melt the particles; particles simply bond through kinetic ener- gy. Non-spherical powder can therefore be used instead, meaning the TKF process enables significant time, cost and energy efficiencies by eliminating the need for extensive re- finement of the raw mineral feedstock.
“That’s why this process is more sustainable than oth- ers; we don’t need energy to melt the particles,” Koeck said. “Accelerating the powder is way more energy efficient then melting the powder particles.”
“This combination of lower energy rates in production, and using a raw material which consumes less energy in its production to start with, makes us very energy efficient. That's where the ‘green titanium’ story is coming from.”
Koeck notes that a further sustainability factor comes from the fact that titanium itself is highly chemically and thermally stable and can therefore create components with greater longevity.
“If certain components on satellites are in space and they continue to work for years instead of months, there you have another indirect benefit to the environment, simply because they last longer,” he said.
“I think as more and more companies are starting to also
BOEING