PROCESS AND INSTALLATION FOR IN-SITU PRODUCING COMPOSITE MATERIALS WITH MATRIX OF ALUMINIUM ALLOYS AND REINFORCING CARBIDE PARTICLES

摘要

The invention relates to a process and installation for producing composite materials with aluminium alloys matrix alloyed with carbide-forming elements such as Si, Ti or the like, reinforced with Si or Ti carbide ceramic particles, or ceramic particles of other carbides, obtained by an in-situ process taking place in argon atmosphere by injecting methane gas introduced into the mixture. The claimed process is based on the chemical processes of dissociating methane gas and on the reaction between the formed carbon and the silicon in the liquid alloy, at temperatures in the range of 900...1100°C, the reaction between the carbon and the silicon taking place simultaneously with the reaction between carbon and aluminium and having the following stages: dissociating methane into carbon and hydrogen particles, diffusing the carbon particles towards the melt/gas interface, diffusing the carbon particles into the melt and reacting the carbon with the silicon in the melt with the nucleation and growth of SiC-monomer particles and SiC-crystal-particles, the composites with Al-Si alloy matrix and SiC reinforcing particles, with small sizes of 5...10 μ, are prepared by injecting the mixture of gas 10% CH/90% Ar into the liquid alloy matrix containing at least 7% Si and 0.5...0.7 % Mg, at temperatures ranging between 900...1100°C for 5...10 h, cooling and remelting the primary composite at 670...700°C for 5...10 min for homogenization, followed by mould casting. The claimed installation has a melting-reaction chamber () with a cover () cooled with water, two pipes connections () through which the cooling water circulates continuously, a pipe connection through which the protection gas circulates together with the resulting gases, a melting-reaction crucible () is inserted into the chamber (), said crucible having some nozzles with the diameter of 1 mm machined at the lower part, through which the reactive gas () is injected.