Publication

Abstract : The Al LM25/TiB2 (10 wt %) composite is fabricated using in-situ process by stir casting method. LM25 alloy is melted in a graphite crucible at 8000C using electric furnace in argon gas atmosphere and a mixture of K2TiF6 and KBF4 is added to the melt gradually through the hopper attached at the top of the furnace. The melt is stirred with the aid of mechanical stirrer which rotates at 200 rpm for 40 minutes intermittently. The reaction between K2TiF6 and KBF4 in those conditions results in the formation of TiB2. This melt is poured in the stainless steel mould which is preheated at 2000C and the obtained casting have dimension 100 mm length and 20 mm diameter. The composite specimens are then machined according to the specification requirement of the experiments. All the specimens are polished using emery sheets of grade 1/0 and 2/0 followed by velvet polisher. The specimen used for microstructure analysis is further etched with Keller's reagent. Spectroscopy of LM25 alloy is carried out to observe its elemental composition. X-ray diffraction is used to ensure the formation of TiB2 during casting process. Inverted metallurgical microscope and Vickers hardness tester are used to study the microstructure and micro hardness of the fabricated composite respectively. The X-ray diffraction results revealed the formation of TiB2 particles in the fabricated composite. Microstructure analysis revealed uniform distribution of TiB2 in the aluminum matrix and Micro hardness test shows an increase in hardness of the composite (91HV) as compared to the un reinforced alloy (82HV) by 10%. © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved.