Effect of coated B4C reinforcement on mechanical properties of squeeze cast A356 composites

Abstract

In the present study, attempts were made to coat the B4C powders with TiB2 via a sol-gel process, and then squeeze cast A356 matrix composites reinforced with coated B4C particles were fabricated. X-ray diffraction studies also confirmed the existence of boron carbide and some other reaction products such as TiB2, AlB2 and Al3BC in composite samples. It was observed that the amount of porosity increased with increasing the volume fraction of composites. Tensile behavior and hardness of unreinforced alloy and composites were evaluated. It was noted that the elastic constant, strain-hardening and UTS of the metal matrix composites (MMCs) were higher than those of the un-reinforced Al alloy and increased with increasing of coated B4C content. The strengthening of particulate reinforced metal-matrix composites is associated with a high dislocation density in the matrix due to the difference in coefficient of thermal expansion between the reinforcement and the matrix. K e y w o r d s : MMCs, aluminum, boron carbide, sol-gel processing

Effect of Fly Ash Addition on the Physical and Mechanical Properties of AA6063 Alloy Reinforcement

“…Furthermore, there were increasing numbers of heterogeneous pore nucleation sites inside composite structures [41,42]. These types of porosity defects were usually found to be connected with groups of fly ash particles and they were rarely observed in the matrix surface when there are samples with a high content of fly ash (12 wt %; Figure 8).…”

“…Other factors that influence the increase in the porosity of composites was insufficient to explain the gaps between adjacent ash particles due to expected increases in the effective viscosity of casting melts resulting in a higher gas holdup [40] and improper feeding of liquid metal [37]. Furthermore, there were increasing numbers of heterogeneous pore nucleation sites inside composite structures [41,42]. These types of porosity defects were usually found to be connected with groups of fly ash particles and they were rarely observed in the matrix surface when there are samples with a high content of fly ash (12 wt %; Figure 8).…”

Effect of temperature, time, and shear force on the morphology and size of dendrites in A356-Al2O3 composites

“…Currently, composites are employed in industries such as aerospace, transportation, automotive, electrical industries, and solar energy. 5–9 Metal matrix composites contain a ductile and deformable metallic matrix reinforced with high strength ceramic phases. 10 Aluminum matrix composites have been widely used in various industrial applications where high strength to density ratio, high wear and corrosion resistance and good fatigue properties are required.…”

Mechanical Properties as a Function of Casting Process of Aluminum–Silicon Alloy Matrix Composites

“…Assuming complete connection and uniform distribution of particles, and ineffectiveness of changing the shape of the matrix and reinforcing phases on each other, the simplest way to predict the behavior of the composition of the composite is the classic law of the mixtures [8,9]. But in most cases, the strength and formulation obtained from empirical calculations is significantly lower than the values obtained from the mixing rule.…”