Enhancement of microstructure uniformity and grain refining efficiency of Al-5Ti-1B alloy via powder extrusion

Microstructure uniformity and grain refining efficiency of Al-5Ti-1B alloy rod prepared by powder extruded process and continuous casting and rolling process are investigated in detail by X ray diffractometer, scanning electron microscope and electron probe. It is found that TiB 2 and TiAl 3 particles are uniformly distributed in the powder extruded Al-5Ti-1B alloy via gas atomization and hot extrusion process. The samples with 0.2% powder extruded Al-5Ti-1B alloy rod holding for 2 min consist of equiaxed grains with an average diameter of 183 µm. Even the holding time extended to 180 min, the average diameter is still stable (229 µm). Al-5Ti-1B alloy rod prepared by the powder extruded process presents better grain refinement and stronger resistance to grain coarsening.