TiB particulate-reinforced Ti-22Al-27Nb (mol.%) matrix composites were prepared by the gas atomization powder metallurgy method. Gas-atomized powder, with particle diameters ranging from 45 μm to 150 μm, was poured into an evacuated stainless steel can and compacted by hot isostatic pressing (HIP) at 1373 K with 200 MPa pressure. The HIP'ed materials were hot-rolled into 12-mm square bars at 1423 K and subsequently subjected to the B2 anneal treatment, in which hot-rolled composites were held at 1523 K for 3.6 ks and cooled at a rate of 0.03 K/s. The TiB particulates in the composites were extremely small, with diameters of less than 1 μm and lengths ranging from 1 to 10 μm. The room temperature tensile and high cycle fatigue properties of the composites were compared to those of an unreinforced matrix alloy and composites produced by the conventional ingot metallurgy method, which creates larger (about 10 μm diameter and 50 μm length) TiB particulates.
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