Synthesis and Characterization of /N-S/TU Al-TiB_2 Metal Matrix Composites

摘要

An in-situ Al-5%TiB_2 metal matrix composite has been prepared by melting together an Al-3.45%Ti and an Al-1.55%B master alloy at 1000°C for 60 minutes. The Al-3.45%Ti and Al-1.55%B master alloys were prepared separately by the reaction of molten Al with K_2TiF_6 and KBF_4 salts respectively at 800°C for 60 minutes. An attempt was also made to prepare the in-situ composite by the reactions of molten aluminium with the mixed K_2TiF_6 and KBF_4 salts (taken in an appropriate ratio) at 800°C for 60 minutes. Optical microscopy, XRD, SEM and EDS X-ray microanalysis characterized the microstruct ural features of the MMCs so prepared with particular reference to the reinforcing TiB_2 particles formed. The study revealed that reaction of molten Al with the mixed K_2TiF_6 and KBF_4 salts results in extensive formation of Al_3Ti and very small fraction of TiB_2. The melting together of the Al-Ti and Al-B master alloys at 1000°C for 60 minutes in a resistance furnace resulted in the formation of TiB_2 particles mostly in the size range of 10-35 microns.