The Characteristics of Alumina Particle Reinforced Pure Al Matrix Composite

Abstract

Al 2 O 3 is widely used as the reinforcing additive in the metal matrix composites. The influence of Al 2 O 3 particle size on the density, hardness, microstructure, yield stress, compression strength, and elongation of the sintered Al-Al 2 O 3 composites were investigated. In the present study, 10 wt% of Al 2 O 3 powder with three different particle sizes (3, 12 and 48 µm) were used in the production of the samples. Powder metallurgy technique was utilized to obtain more homogeneous Al 2 O 3 distribution across the composites. The samples were cold pressed at 440 MPa, and sintered at 550 • C for 45 min. Results showed that the relative density of the composite was initially increased with decreasing particle size. However, it was decreased with further particle size reduction. It was also pointed out that the mechanical properties of the specimens were increased with decreasing particle size. The grain size and particle distribution homogeneity was decreased with raising the particle size.

High Strain Rate Tensile and Compressive Testing and Performance of Mesoporous Invar (FeNi36) Matrix Syntactic Foams Produced by Feedstock Extrusion

“…Non‐metallic particles − as in this case, the hollow spheres − are known to restrict grain boundary movement in the metal matrix and, therefore, grain growth during sintering. A high number of small particles are more effective than few large particles in this respect . Even though the hollow spheres are significantly larger than non‐metallic particles commonly used in MMC (typically <20 μm), the refining effect can still clearly be discerned when comparing Figure and 2: The grain size of the Invar matrix of the syntactic foam is reduced in comparison to that of the compact matrix material.…”

Hardness and Elastic Modulus of Al-Based Composite Developed from Aluminium Piston Scraps Using Alumina and Snail shell as Reinforcements

“…The experimental and theoretical hardness values of sample 3 (45.50 RHN and 18.28 GPa) are greater than for sample 11 (39.42 RHN and 17.24. GPa) indicating that alumina contributes to the hardness more than the snailshells (Parvin & Rahimian, 2012). This trend however differs for sample 7 and 8 where experimental hardness value reduced with increased Al composition.…”

“…As indicated, sample 7 which was reinforced with 5 wt.% snailshells has hardness value of 41.2 RHN and modulus of resilience of 56.1 GPa while sample 2 with similar fraction of snailshells has higher hardness value of 51.2 RHN but a lower modulus of resilience of 25.8 GPa. This implies that the higher value of alumina in sample 2 enhances hardness of the composite because the hardness of Al2O3 is significantly harder than pure aluminium thereby hinders the movement of dislocation during deformation (Parvin & Rahimian, 2012). The hardening property of snailshells is attributed to its elemental composition which are CaCO3, C and SiO2 .…”

THE INFLUENCE OF SiC PARTICLE SIZE ON MECHANICAL PROPERTIES OF ALUMINIUM MATRIX COMPOSITES

“…For the same reinforcing phase content, the number of SiC particles increases with the reduction of the particle size of the reinforcement. Therefore, dislocation strengthening is higher for the finer particles of the reinforcement [11]. The coarse fraction of SiC particles might also act as a potential region for a crack initiation point and, thus, cause the mechanical performance to degrade.…”