In situ aluminium based dual matrix hybrid composite through powder metallurgy route for automotive industries

Abstract

In recent times, the focus of researchers worldwide has shifted from monolithic materials to composite materials, primarily due to the need for high performance and affordable materials. Amongst the various types of composite materials, aluminum metal matrix composites (AMMC) are an excellent choice for manufacturing high-specific-strength automotive components, as well as for various mechanical and tribological applications. They are preferred over other materials because of their lighter weight, which is around one-third as much as steel per cubic meter. This property not only ensures more energy-efficient automobiles but also facilitates their production at a lower cost.This study was carried out to attain a deeper understanding of the structural performance of AMMCs. For this purpose, a simple Al-H3BO3-TiO2 system was utilized for AMMC production through ball milling, cold pressing, and sintering. The ball milling process was found to have a considerable impact on particle growth, and the in situ generated reinforcements provide several benefits, including strong bonding and clean particle-metal interface. During the sintering procedure, reinforcement particles were created and uniformly distributed throughout the Aluminium matrix. AMMC's dual matrix structure was observed to perform as a desired characteristic, increasing both ductility and toughness.The percentage of added external aluminum varied from 0% to 25% to 50% to 75% of the total sample. Differential thermal analysis of the green sample was performed up to 800°C, which indicated that the particle development took place after 550°C. Consequently, the sintering temperature was chosen from 600°C to 800°C. Initial microstructural analysis was carried out using optical microscopy, while scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were utilized to examine the morphological and structural reinforcing effects of AMMCs.The presence of various in situ reinforcements, including γAl2O3, AlB2, B2O3, TiB2, and TiAlin aluminum matrix was confirmed through X-ray diffraction (XRD) analysis.The mechanical properties were evaluated using a diametral compression tester and a Brinell hardness tester. It was observed that hardness increased with higher sintering temperatures. The sample sintered at 800°C with 0%unmilled aluminum exhibited the highest hardness of 169.2 HV. The results showed that the highest toughness, approximately 6.12 J/m-3, was found in the 75% external aluminum dual matrix compositessintered at 800°C.