Characterizing an in situ TiB2 particulates reinforced aluminium-based composite and its heat treatment

Metal matrix composites were fabricated in an Al-6Cu-0.2Mg-1Mn matrix reinforced by particulates of in-situ TiB2 from a reaction process via K2TiF6 and KBF4 salts in the matrix. Different percentage of the TiB2 particulates, 1 wt-%, 3 wt-% and 5 wt-%, respectively, was employed for the composite. A series of heat treatments comprised of solution treatment and aging were carried out on the composites. Phases, microstructures and Vickers' hardness were revealed for the differently treated composites and Al-6Cu-0.2Mg-1Mn alloy. The results showed that the in-situ TiB2 particulates could improve the structure of the matrix by retarding a directional growth of the matrix grains and forming isometric grains in the matrix. Remelting the composite with 3 wt-% TiB2 tended to weaken TiB2 particulates' clustering. A significant effect on the refinement of the grains was observed when the content of TiB2 particulates was increased from 0 to 5 wt-%. And the Vickers' hardness of the differently treated composites with 3 wt-% or 5 wt-% TiB2 was higher than that of the corresponding Al-6Cu-0.2Mg-1Mn alloys. The composite's precipitation rate was accelerated with the increase of the content of TiB2 particles during aging at 170 degrees C. (C) 2013 The Authors. Published by Elsevier B.V. Open access under CC BY-NC-ND license.