A composition for making a core for use in a moulding or casting process, a core comprising said composition, and a mould for producing an article by high pressure die casting or semi-solid casting. The composition comprises a particulate refractory material, a binder composition comprising at least one hydrophilic polymer, comprising at least one polysaccharide or polysaccharide derivative; and at least one pozzolanic additive. The mould comprises a core for defining an internal cavity of the article and the core comprises a solidified core composition. The solidified core composition comprises a particulate refractory material and a binder composition, degrades in water such that a cylinder of the solidified core composition having a maximum height of 80 mm and a maximum diameter of 50 mm disintegrates in no more than 10 minutes when immersed in water at a temperature of 20 C. and stirred at a speed of 60 rpm, and has a flexural strength of at least 300 N/cm.sup.2. The invention also resides in a method for producing an article by high pressure die casting or semi-solid casting.

Molding core for manufacturing an OMC hollow aeronautical part, in particular a fan module part, including a composite material including on the one hand a first phase of formula M.sub.n+1AlC.sub.n, where n=1 to 3, and M being a transition metal selected from the group consisting of titanium, niobium, chromium or zirconium, the composite material including on the other hand a second phase of formula Al.sub.4C.sub.3.