Mechanical And Tribological Behaviour Of Al-B4b Lab Report

The present work investigates the mechanical properties and tribological behavior of Al-B4C composites. Attempts were made to overcome the wetting problem between B4C and liquid aluminium at lower temperatures for promising the mechanical and tribological behaviour of the Al -B4C composites. AA6061-B4C particle reinforced composites were produced through casting route at 850ºC with K2TiF6 added as flux to overcome the wetting problem between B4C and liquid aluminium metal. The Aluminium B4C composite samples were subsequently subjected to T6 heat treatment. The composite samples thus produced were then characterized by hardness, compression and wear test. The results showed that the hardness of the composites increased with increasing B4C particle
High strength to weight ratio, environmental resistance, high stiffness and good wear resistance are the characteristics that encourages more research to develop their applications with further improvement in the properties. Ceramic particles such as SiC, Al2O3, B4C, TiC and TiB2 are the widely used materials for reinforcement of aluminium [1]. Boron carbide (B4C) is one of the most promising ceramic materials due to its high strength, low density (2.52 g/cm3), high hardness, good chemical stability and neutron absorption capability [2-4]. Because of its high hardness B4C can be an alternative to SiC and Al2O3 for reinforcing AMCs particularly for applications where a good wear resistance is important. Aluminium B4C composites find their applications in nuclear industries particularly because of the ability of B10 isotope to capture neutrons
Aluminum requires a temperature as high as 1100°C for wetting the B4C surface completely [9-10]. At such high temperature the processing leads to the formation of undesirable compounds such as Al3BC, AlB2 and Al4C3 due to the chemical reactions between Al and B4C. These reaction products degrade the mechanical properties of the composites [11].A problem with production of MMCs is the chemical compatibility between the matrix and the reinforcement particularly when using liquid metal process . Casting MMCs is an attractive process because it is relatively inexpensive and provides for a wide selection of the materials and processing conditions. Al-B4C composites can be processed with low cost casting routes [12-13]. But the wetting between Al-B4C is poor below 1100°C and this possess the difficulty in the production of Al-B4C composites by mixing particles into the liquid phase. To overcome the difficulty and to improve their wettability and incorporation into Aluminium melts the ceramics are generally heat treated or coated[14]. Titanium is one of the reactive metals that can be used to enhance wettability in Al-B4C systems [15]. The objective of the present investigation is to study the mechanical properties and tribological behavior of Al-B4C composites fabricated through casting route with addition of K2TiF6 flux forming