Micropillar Compression in As-Solidified and Ultrafine-Grained Inhomogeneous Al-TiC Nanocomposites: A Comparative Study




Abstract: The as-solidified and ultrafine-grained (~466nm) pseudo-dispersion Al-7vol.%TiC nanocomposites were manufactured by solidification nanoprocessing and high pressure torsion (HPT). The microstructures mainly consisted of the α-Al matrix and DO22-Al3Ti intermetallic, as well as TiC domains, mechanical response of which were linked by micropillar compression methodology. Flow stresses of the single-crystalline Al and Al3Ti pillars dramatically increased as the pillar became smaller, i.e. smaller is stronger. ‘Smaller is weaker’ was observed and a remarkable yield strength (~720MPa) was obtained for Al-30vol.%TiC composite pillars. The considerable micro-plasticity (~10%) was obtained in notorious brittle DO22-Al3Ti compound. Uniform and irregular slip bands were observed in the single-crystalline and composite pillars respectively. Finally, using high resolution TEM, we observed numerous nanotwins and edge dislocations in the [Al+TiC] mixture and inside TiC nanoparticles.

Authors: Zuqi Hu, Chezheng Cao, Marta Pozuelo, Suveen Mathaudhu, Christian Roach, Xiaochun Li, and Jenn Ming Yang

Keywords: Al TiC nanocomposite Micropillar In situ compression Deformation

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8 pages


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