Novel Separation Technique of Particle Reinforced Metal Matrix Composites by Fused Deposition Method

Abstract

To develop a novel separation technique of matrix alloys from metal matrix composite, separation experiments for various kinds of particle reinforced metal matrix composites (PRMMCs) were carried out. The Al-4mass%Cu alloy, Al-7mass%Si alloy and cast iron were used as matrix. The SiC particles (particle size: 75μm) and Al2O3 particles (particle size: 120μm) were used as reinforcement. The PRMMC specimen was placed in a silica tube container with a small nozzle (nozzle size: 0.75mm) at the bottom and was melted by H.F. induction heating. Then the molten PRMMC specimen was forced to flow out through the nozzle by applying a certain pressure of Ar gas. Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container consisted of the reinforcements and a part of the matrix alloy. The amount of separated matrix alloy increased with decreasing the volume fraction of reinforcement particles in PRMMC specimens. With decreasing the fabrication temperature from 1273K to 1073K, the amount of matrix alloy separated from SiCP/Al-7mass%Si alloy composites increased. It is considered that a reaction layer formed on the surface of SiC particles at 1273K improves the wettability between the molten matrix alloy and SiC particle, which prevents the separation of molten matrix alloy from reinforcements. On the other hand, the amount of separated matrix alloy from 20vol% Al2O3P/cast iron composites was very high due to no reaction layer formed at interface between Al2O3 particle and cast iron.