Effect of different oxide layer shares on the upsetting of titanium aluminide specimens

Abstract. By ball milling in a low-oxygen atmosphere, it was possible to show that titanium aluminides (TiAl) can be processed into components by pressing and sintering in the same atmosphere. The properties (e.g. hardness and density) that can be realised with established processes such as field-assisted sintering (FAST) or hot isostatic pressing (HIP) were not achieved. Pores in the component are closed by forming processes, which improves the mechanical properties. In this work, powder-metallurgically processed TiAl was hot-formed in a low-oxygen atmosphere. The forging parameters and pre-consolidation were characterised with regard to their effect on the component properties. Force, hardness and porosity measurements as well as metallographic analyses were used to evaluate the process and the resulting specimens. It was found that a pre-consolidation and a higher degree of deformation lead to a lower porosity and a higher hardness.