Mechanical chacterization of PA Al2O3 composites obtained by selective laser sintering

The increasing need for strongly personalized products, to be produced in few parts with short time-to-market, makes Rapid Tooling and Manufacturing competitive with respect to traditional processes. The great advantages, in terms of reduced times and costs for the product’s launching, can be properly exploited only through a deep knowledge concerning the parts’ performances as a function of the construction process. A promising material for application in SLS technology is PA-Al2O3 composite. An experimental campaign was started and some specimens, with different orientations in regard to powder deposition plane and laser path, have been manufactured and tested. Mechanical properties have been determined using tensile test performed both at room temperature and at 100 °C. 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