Titanium alloys are essential materials for mobility (aerospace, automotive industry), medical technology (e.g. hip joint implants, osteosynthesis), food and pharmaceutical technology, electrical engineering as well as water and offshore technology due to the material's low density, good specific mechanical properties and high corrosion resistance. One disadvantage is that the production of titanium is particularly energy-intensive due to the high oxidation tendency and therefore six times more expensive than that of steel. Furthermore, the EU is almost 100% dependent on imports.

Titanium is often used for the manufacturing of highly complex, lightweight components where during fabrication a very large amount of waste in the form of chips is generated. Conventional recycling by remelting requires again a lot of energy and is mostly carried out outside the EU.

In this work we show alternative, more sustainable routes for the direct recycling of titanium chips by using them as starting raw material for advanced manufacturing. This will save energy and shorten transport routes, thus improving the entire value chain of high-quality titanium products. Different liquid phase and solid phase recycling methods are highlighted and compared in detail.

Cleaned Ti chips can replace the usual raw material – wire or powder – for additive manufacturing (AM) by direct energy deposition (DED) using a plasma arc as energy source, called plasma metal deposition (PMD). The method is able to produce large scale, near-net shaped components with highly complex appearance without the above-mentioned high amount of swarf. Thus, it combines two sustainable approaches. Dense material can also be recycled from Ti swarf by hot pressing technologies. A further solid-state recycling method is presented via the processing of Ti chips by severe plastic deformation (SPD). Here, the required processing temperatures are lower than in case of hot pressing but the high degree of deformation in combination with a high hydrostatic pressure allow the consolidation of the Ti swarf. In this case the microstructure is further refined which has a beneficial effect on the mechanical properties.