The microstructures and mechanical properties of Al-15Si-2.5Cu-0.5Mg/(wt%)B4C composites produced through hot pressing technique and subjected to hot extrusion

In this study, B4C (5, 10, and 15 wt%) particle-reinforced Ecka Alumix 231® aluminum matrix composites were produced through the hot pressing technique. Some of these samples were subjected to hot extrusion as a secondary treatment at 4:1 ratio at a temperature of 555 °C. The obtained samples were subjected to density measurement, hardness test, microstructure analysis, and three-point bending test, and their fracture surfaces were examined. A density of over 99% was found in the samples. Al-rich solid solution and primary Si, CuAl2, Al2CuMg, and Mg2Si phases in the microstructure were determined through X-ray diffraction analysis. Grain sizes were found to be 20 μm and 2 μm in the microstructures of the samples produced through hot pressing technique and of those subjected to additional hot extrusion, respectively. High hardness values were obtained in the samples subjected to hot extrusion. In these samples, wt% B4C particle ratio and transverse rupture strength increased considerably. Furthermore, the highest compressive strain value was obtained in the 10 wt% B4C particle-reinforced composites subjected to hot extrusion.