Semi-solid extrusion of TiCp/2024Al composites prepared
by contact reaction method①
by contact reaction method①
(School of Materials Science and Engineering, Harbin Institute of Technology,
Harbin 150001, P.R.China)
Harbin 150001, P.R.China)
Abstract: The contact reaction method was employed to prepare TiCp/2024Al composites and the semi-solid extrusion was employed to manufacture composite rods. Through many experiments, suitable processing parameters were obtained, under which sound rods can be fabricated. It is found from the extrusion pressure—stroke curves of semi-solid extrusion that the deformation force during semi-solid extrusion is low and steady. The reason for lower extrusion pressure of semisolid extrusion was given. Some fabrication defects, such as break-out and excessive extrusion force, owing to the inappropriate selection of processing parameters were also observed. The microstructures of TiCp/2024Al composites are characterized by well-densified matrix, uniformly distributed TiC particles, some banded particle clusters and realignment of TiC particles along the extrusion direction, and no fracture of TiC particles. The mechanical properties of TiCp/2024Al composites are much higher than those of unreinforced alloy. In the meantime, the elongations of the composites are maintained at the level enough for practical applications.
Key words: TiCp/2024Al; semi-solid extrusion; microstructure; mechanical properties