Early anisotropic expansion of aluminium foam precursors

摘要: This work reports a detailed study on the early expansion (before melting point) of powder metallurgical (PM) aluminium foam precursors and its influence intrinsic anisotropy existing in final cellular structure PM foams. Hot uniaxial compressed tablets, rectangular cylindrical extruded profiles thixocast have been considered to evaluate effect processing technique behaviour. An optical device has used register, situ, dissimilar three spatial directions. Cellular morphology examined by X-ray microtomography correlated Results demonstrated high correlation with debonding preferential directions which, combination TiH2 decomposition, generates elongated cracks causes an anisotropic at foaming stages. As consequence, remaining structural is found solid material, even porosities. A discussion possible factors affecting this behaviour, complemented solutions minimize it, provided paper.