Mechanical Characterisation of PA Al203 composites obtained by Selective Laser Sintering

This paper aims to develop a deep charaderization of PA-Al2O3 composite for selective laser sintering (SLS). Tension test is used to determine main mechanical characteristics of the material, both at room temperature and al 100°C. An accurate knowledge of the parts' performances as a function of the building orientation, is fundamental to understand the manufacturing anisotropy. Particular attention is dedicated to the joining and failure micromechanisms ruling the macroscopic characteristics, on the basis of the knowledge developed by the authors on SLS of both metal and polymeric powders. The sintered material shows an evident anisotropy in the growth direction (z-axis), as well as it seems to be not sensitive to the sintering direction at room temperature (x, y, xy). At 100°C the effect of sintering direction becomes more evident and a different behaviour results considering x- and y-direction. respectively. Accurate SEM characterization has been carried out to understand the effect of the manufacturing anisotropy on the mechanical performances, both in terms of additive construction and laser sintering strategy. The observation of the rupture surfaces showed that cracks originate from the external surface and propagate initially by the ductile failure of the polymeric matrix, up to the sudden fracture of the whole section.