Metastable nanostructures with enhanced hardness of Ti-Ni-Al alloy through electrostatic levitation processing

We prepared a Ti-Ni-Al alloy comprised of metastable equiaxed (βTi) dendrites and interdendritic Ti₂Ni phase by means of electrostatic levitation plus quenching. It exhibited an impressive improvement in hardness compared with the sample through DTA processing. By employing the double Cs corrector transmission electron microscope characterization, the coherent solute cluster and semi-coherent nano-distortion (βTi) were found to form within the metastable (βTi) dendrites, and (αTi) nanoprecipitates generated inside interdendritic Ti₂Ni phase matrix. These dispersive metastable nanostructures and the novel (αTi) + Ti₂Ni biphase boundary contributed cooperatively to pinning dislocation. The harmonic cooperation of precipitation strengthening, solution strengthening and fine-grained strengthening were realized to enhance the alloy.