PM processing and characterisation of Ti–7Fe low cost titanium alloys

This work studies a set of low cost beta alloys with the composition Ti-7Fe, processed by conventional powder metallurgy (PM). The materials were prepared by conventional blending of elemental Ti hydride-dehydride powder with three different Fe powder additions: water atomised Fe, Fe carbonyl and master alloy Fe-25Ti. The optimal sintering behaviour and the best mechanical properties were attained with the use of Fe carbonyl powder, which reached a sintered density of up to 93% of the theoretical density, with UTS values of 800 MPa in the 'as sintered' condition. Coarse water atomised powder particles promoted reactive sintering, and coarse porosity was found due to the coalescence of Kirkendall porosity and by the pores generated during the exothermic reaction between Ti and Fe. The addition of Fe-25Ti produced brittle materials, as its low purity (91·5%) was found to be unsuitable for formulating Ti alloysThe authors would like to acknowledge financial support from the Comunidad de Madrid to carry out this research through the programme ESTRUMAT-CM (reference MAT/77), and from the Ministry of Education through the R&D Project MAT2006-02458.Publicad