Spongy metal with ceramic spheres succumbed to the angle grinder and drill

British and German scientists have developed a material of sponge titanium-aluminum alloy with ceramic spheres of aluminum oxide. The new material is about seven times lighter than steel, resists cutting with a circular saw and waterjet cutting, and adding a nichrome alloy and can withstand drilling. Article published in the journal Scientific Reports.

In nature, many materials possess a hierarchical structure at different scales, to resist extreme loads. For example, grapefruit is not destroyed after a fall from a height of ten meters due to the cell structure with a rigid frame, fish Arapaima gigas can withstand the bite of piranhas through a plywood packing of collagen in the scales and shells of abalone , crystals of aragonite, bonded in an organic matrix, three thousand times strongerthan just crystals of aragonite.

Scientists also want to durable materials with the selection of the desired morphology at different levels of the material, but, unlike nature, can use metals that have significantly hardened due to local defects. So, recently, materials scientists significantly advanced metal 3D printing, which you can use to the most complex microstructures, however, the focus on repeatability of the unit cell limits the scope of substances to be used. Materials with the restructuring forms are considered to be promising for extreme loads by mechanical action, they can significantly alter the morphology at small scales and to return to its original state after it — as natural objects. One of the manifestations of such restructuring is the conversion of input mechanical energy to a local oscillation of material.

Staniszewski Stefan (Stefan Szyniszewski) with colleagues from the University of Durham and fraunhoferstra Institute has created a new composite material “Proteus” from spongy titanium alloy-aluminum with ceramic spheres of aluminum oxide. The elasticity of the new material meets the metal part, and the hardness of the ceramic. This material is sensitive to internal fluctuations in local loads and weighs seven times less than steel due to the porous structure.

To obtain material powders of aluminium and titanium hydride, you need to mix and subjected to cold forming, then the mixture you need to squeeze through the extruder and the resulting rods cut into small pieces. Then between the steel plates need to put metal cylinders and a network of ceramic spheres of aluminum oxide. After this, the workpiece must be heated to 760 degrees Celsius for 15-20 minutes, during which decomposes the titanium hydride and the departing hydrogen makes a spongy structure between the ceramic spheres.

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