Abstract

Due to its low density combined with good strength, high corrosion resistance and biocompatibility, titanium is a highly demanded raw material, particularly in the aerospace and medical technology sectors. Since titanium materials are usually used to manufacture high-quality components with complex shapes, a very large amount of waste is produced in the form of chips - often 80% of the starting material. Although the chips can be partially recycled by melting, the process is energy-intensive and is mostly carried out outside the EU. 

The aim of the DiRecT project is to make the recycling of titanium chips more sustainable by saving energy and shortening transportation routes, thus improving the entire value chain of high-quality titanium products. Therefore, various new technologies will be developed and evaluated. In addition to direct recycling of the chips into semi-finished products, from which various products can then be manufactured by conventional processing steps, possibilities for direct upcycling will also be developed. Thereby, either near-net-shape components will be produced directly from chips, which then require only minor machining to obtain the desired product, or the recycled semi-finished products will exhibit improved mechanical properties and are thus suitable for particularly high-quality products.

The novel technologies are (i) plasma metal deposition (PMD), a 3D printing process based on plasma welding, which will be develop to the point where chips can be processed directly instead of the usual starting materials (wire or powder), (ii) Severe Plastic Deformation (SPD), which is intended to consolidate the chips in a single step and refine the microstructure, thus improving the mechanical properties, and (iii) rapid hot pressing using Spark Plasma Sintering/Field Assisted Sintering (SPS/FAST), which will be further developed in terms of the starting material - from powder to chips.

The aim of the project consortium consisting of two Austrian SMEs, RHP-Technology GmbH and SBI GmbH, and the University of Vienna, Faculty of Physics as a scientific partner, is to be able to provide materials produced from chips at the end of the project that meet or exceed the requirements of the standards for titanium materials in terms of density, purity and mechanical properties. Evaluation of the energy balance and material yield of the various methods are other important aspects of the project. 

The innovative recycling and upcycling methods developed in the project will enable titanium processing companies to bring more environmentally sustainable products to market. The resource and energy savings and avoidance of long transportation routes make a general contribution to sustainable production and circular economy and have a positive impact on the environment and climate.