Surface inoculation of aluminium powders for additive manufacturing of Al-7075 alloys

Abstract

For laser powder bed fusion (LPBF), particularly during solidification after the laser melting process the generation of high-strength aluminium materials (such as Al-7075) possesses a particular challenge, since the high energy input often causes defects like pores and cracks in the material. To overcome this issue, nanoparticles were adsorbed on the surface of the powder used for the L-PBF process. This addition aims at the grain refinement and thereby at the reduction of of hot crack formation during the manufacturing process. This contribution presents the process of surface inoculation of aluminium particles with TiC nanoparticles, as well as the measurement of the melting and solidification temperature by means oof differential fast scanning calorimetry (DFSC). With the help of DFSC, a modified solidification process could be observed. Accordingly, the nanoparticles act as nuclei with improved nucleation barrier during the rapid solidification of the aluminium powder.