Study on the Compressibility of TiAl48-2-2 Powder Mixed with Elemental Powders

Many metallic powder materials can be processed fast and cost-effectively using the conventional powder metallurgy method. For this purpose, the metal powder is pressed into a compact and then sintered in a furnace to produce a finished component. Gamma titanium aluminides are an exception to this. Due to their brittleness, they cannot be compacted in classical die pressing. A promising approach is the addition of elemental significantly more ductile alloy powder. The aim of this work is to investigate the influence of the admixture of elemental powder on the compressibility and the properties after the sintering process. Within the scope of the work, commercially available pre-alloyed TiAl48-2-2 (GE48) powder, which is applied e.g. for turbine blades in aircraft, is used. The powder alloy is mixed with elemental titanium, aluminium, chromium and niobium powder according to its composition and then pressed to a compact. Selected samples are sintered and metallographically characterised. By varying the pressing load and the proportion of elemental powder, as well as the proportion of elemental powder mixtures, the influence on the compaction behaviour and the mechanical properties is investigated. It is possible to produce compacts with sufficient mechanical properties by adding specific proportions of different elemental powders depending on the element and the compaction parameters. The results show a significant dependence of the relative density and tensile splitting strength on the proportion and type of elemental powder added.