Researchers from the Department of Defence and RMIT University have demonstrated that additive manufacturing, or 3D printing, of lightweight titanium could become a viable option for military vehicle armour to protect troops.
Until now, steel has been the go-to choice for armour because of its strength and hardness. However, steel armour adds substantial weight, which can affect the vehicle's speed, range, payload and endurance.
A new additive manufacturing approach pioneered by researchers from RMIT's Centre for Additive Manufacturing, Alex Medvedev and Milan Brandt, has enabled the fabrication of ballistic-grade titanium material.
Researchers have investigated lightweight titanium alloys for military purposes before, however, the high cost of raw materials and the difficulty in machining has meant there has been limited uptake for some applications.
Recent advances in additive manufacturing processes and post-manufacture heat treatment could now make titanium a far more viable option.
Defence materials scientist Darren Edwards said that while additive manufacturing offers great potential thanks to its ability to produce near end-state components rapidly, with highly customised geometries and microstructures on demand, standard additive manufacturing processes using default parameters could result in poorer mechanical properties, such as strength and ductility, compared to traditional manufacture.
"Our research was focused on optimising the fabrication process to achieve the desired ballistic properties of the material," Dr Edwards said.
The team had to overcome a number of technical challenges to achieve the required performance.
"We did a lot of work to determine the influence of microstructure features - the phase composition, the grain structure and crystallographic texture - on the likelihood of failure under high strain-rate ballistic impact," Dr Edwards said.
"We now know the specific microstructures that provide the best ballistic performance.
"RMIT researchers were able to adjust the additive manufacturing processing parameters to significantly increase the ballistic protection of material straight out of the machine."
In addition, the team came up with a new post-manufacture heat treatment that resulted in a considerable increase in ballistic performance, also exceeding both the required benchmark and the performance of commercial off-the-shelf titanium armour plate.
"Our hope is that this research will pave the way for the sovereign manufacture of titanium armour," Dr Edwards said.
Sponsored through the Next Generation Technology Fund, the RMIT research project will continue to investigate further protection improvements that can be obtained via the adoption of innovative additive manufacturing technologies.
