Effects of nanosized TiCp dispersion on the high-temperature tensile strength and ductility of in situ TiCp/Al-Cu-Mg-Si nanocomposites.

Abstract In situ TiC p /Al-Cu-Mg-Si nanocomposites were prepared in Al-Ti-C systems with different carbon sources (pure carbon black, mixed carbon source (50 wt% CNTs + 50 wt% carbon black) and pure CNTs) via a combination of the combustion synthesis, hot press and hot extrusion methods. The in situ TiC p /Al-Cu-Mg-Si nanocomposites synthesized by the mixed carbon source obtained the most uniform distribution of nanosized TiC p , highest yield strength (σ 0.2) and tensile strength (σ UTS) and best fracture strain (ε f). The 30 vol% TiC p /Al-Cu-Mg-Si nanocomposite synthesized by the mixed carbon source showed superior σ 0.2 (217 MPa), σ UTS (251 MPa), and ε f (17.7%) at 533 K, which were respectively 4.3%, 4.1% and 136% higher than those of the nanocomposite synthesized by pure C black (208 MPa, 241 MPa and 7.5%) and respectively 3.8%, 1.6% and 88.3% higher than those of the nanocomposite synthesized by pure CNTs (209 MPa, 247 MPa and 9.4%). The superior high-temperature tensile strength and ductility of the nanocomposites prepared by the mixed carbon source were attributed to the homogeneous distribution of nanosized TiC p. The strengthening of the nanosized TiC p and θ′ precipitates was the main strengthening mechanism of the in situ TiC p /Al-Cu-Mg-Si nanocomposites at high temperatures. Highlights • In situ TiC p /Al nanocomposites are prepared in Al-Ti-C systems with various carbon sources. • Nanocomposites prepared by mixed C/CNTs show the best dispersion of nanosized TiC p. • Nanocomposites prepared by mixed C/CNTs show the best strength and ductility at 493 K and 533 K. [ABSTRACT FROM AUTHOR]