Microstructure and mechanical properties of AA6061–5wt. %TiB2 in-situ metal matrix composite subjected to equal channel angular pressing

Publication date: Available online 23 May 2019Source: Materials Science and Engineering: AAuthor(s): A. Chidambaram, S. Balasivanandha Prabu, K.A. PadmanabhanAbstractAluminum alloy 6061–5wt. %TiB2 in-situ metal matrix composite was produced by a salt-melt reaction between halide salts K2TiF6 and KBF4 inside AA6061 melt. The composites prepared were subjected to equal channel angular pressing (ECAP) up to 10 passes at ∼300 °C (0.45 Tm of AA6061). The improvement in strength and Vickers hardness due to grain refinement and redistribution of in-situ TiB2 particles was studied. The AA6061 (without TiB2) was also subjected to ECAP to identify the improvement arising from the presence of TiB2 particles and their redistribution in the AA6061-TiB2 composite. The microstructures of the AA6061 alloy and the composite were studied using Electron Back Scattered Diffraction (EBSD). The Vickers hardness and tensile strength of the alloy and the composite were evaluated as a function of the variables of the ECAP process. After 10 ECAP passes, the average grain size of AA6061 alloy had decreased from ∼87 ± 11 μm to ∼20 ± 2 μm. In contrast, the average grain size of the AA6061-TiB2 composite after 10 passes had decreased to ∼5 ± 2 μm from ∼37 ± 9 μm. There was an increase in the Vickers hardness of AA6061 alloy from ∼54 ± 1 HV to ∼64 ± 1 HV and the AA6061-TiB2 composite showed a hardness improvement from ∼57 ± 1 HV to ∼69â€...
Source: Materials Science and Engineering: A - Category: Materials Science Source Type: research