Aluminium matrix composites reinforced with AlN particles formed by in situ reaction

摘要

Purpose: Ultrafine reinforcement particles are formed as product of reaction between reactive components. Those kinds of materials have good mechanical properties (higher yield stress and creep resistance). Via in situ reaction between liquid metal and reacting substance (solid or gas) is possible to obtain aluminium matrix composites similar to SAP composites by casting methods. Presented results of researches concerning possibilities of obtaining ultrafine aluminium nitride particles via in situ reaction between aluminium alloys (with addition of Mg) and nitrogen.Design/methodology/approach: The experiments were performed in a reaction chamber, heated in a sylite furnace where the 0.3 MPa pressure of nitrogene were obtained and autoclave furnace at gas pressure of 1 MPa. Samples were heated at 1000°C and held at that temperature for 1 hour at the suitable gas pressure.Findings: The research has shown, that vaporization of Mg and indirect nitridation depend on gas pressure in reaction chamber. At high pressure (1 MPa) of N2 in situ reaction procced in limited scope.Practical implications: Using the in situ reaction in order to form AlN dispersion reinforcement in the aluminium alloy matrix seems possible but the control of the reaction is difficult.Originality/value: During the liquid-phase process, the following factors determine the possibility of controlling the process of the dispersion reinforcement phases' formation: the matrix alloy composition, the temperature, the reactive gas pressure and the time of synthesis