Mechanical characterisation of PAAl2O3 composites obtained by selective Laser Sintering

The increasing need for strongly personalized products, to be produced in few partswith short time-to-market, makes Rapid Tooling and Manufacturing competitive withrespect to traditional processes.The great advantages, in terms of reduced times and costs for the product’slaunching, can be properly exploited only through a deep knowledge concerning theparts’ performances as a function of the construction process.A promising material for application in SLS technology is PA-Al2O3 composite. Anexperimental campaign was started and some specimens, with different orientations inregard to powder deposition plane and laser path, have been manufactured andtested. Mechanical properties have been determined using tensile test performed bothat room temperature and at 100 °C.The sintered material shows an evident anisotropy in the growth direction (z axis), aswell 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 differentbehaviour results considering x and y direction respectively.Accurate SEM characterization has been carried out to understand the effect of themanufacturing anisotropy on the mechanical performances, both in terms of additiveconstruction and laser sintering strategy. The observation of the rupture surfacesshowed that cracks originate from the external surface and propagate initially by theductile failure of the polymeric matrix, up to the sudden fracture of the whole section.