Me Tata

Effect of powder mix composition on Al foam morphology

The effect of mix composition on foam morphology has been examined by image analysis carried out on metallographic sections of Al foams prepared by powder metallurgy. Two sets of samples have been prepared by using SiC particles with mean sizes of 37 and 60 µm. Each set consists of 16 groups of samples with different amounts of TiH2 (0.1, 0.2, 0.4, and 0.6 wt%) and SiC (0.8, 2.8, 6, and 9 wt%). The distribution of SiC particles on the internal walls of the bubbles has been investigated by scanning electron microscopy observations, which evidenced also the presence of particles of another phase, identified as Ti3Al by energy dispersion spectroscopy. Some tests, performed without SiC particles, showed that the Al foaming occurs also under these conditions, however foams exhibit few bubbles of very large size and irregular shape. Experimental data have been used for training two multi-layer feedforward artificial neural networks. The models represent useful tools for predicting morphologic features of foams for any given mix composition in the training range.

Characterization of the Compressive Behaviour of an Al Foam by X-Ray Computerized Tomography

Al metal foams manufactured by the powder-method have been investigated. Compression tests were performed on the same sample at increasing deformation steps: at each stage the sample was observed by X-ray computerized tomography. A geometric evaluation of porosity on many sections was performed by calculating, for each pore, its area, equivalent diameter, perimeter and circularity.

Mechanical and surface properties of Ti-sputtered thin films

The mechanical behaviour of the film and the thickness influence on the surface morphology have been studied in detail for Ti-sputtered coatings deposited at room temperature on AA6082 T6 and AA2618/20% Al2O3 flat samples. The intrinsic hardness and surface roughness of Ti thin films ranging from 0.5 µm to 2 µm have been investigated. The higher the coating thickness (up to 2 µm), the lower the surface roughness and the higher the intrinsic hardness of the film. The improvement of surface roughness has been achieved by Ti-sputtered clusters able to cover the micro-valleys.