Investigating the Improvement of Mechanical Properties and Wear Behavior of Al7075-Nano Al2O3-TiC Composite Manufactured by Spark Plasma Sintering

In this study, a hybrid Al7075-nano Al 2 O 3 -TiC composite was fabricated via spark plasma sintering (SPS) using recycled machining chips. This composite includes TiC and Al 2 O 3 additives to synergistically enhance its mechanical properties. The three-point bending strength, hardness, wear, and density of the sintered composites were measured. Key findings demonstrate that the ST6-2.5 T-1A composite (2.5 wt.% TiC, 1 wt.% nano-Al 2 O 3 ) achieved optimal performance: a Vickers hardness of 1490 HV and three-point bending strength of 682 MPa, comparable to T6-treated Al7075. Tribological tests revealed a 40% reduction in wear track depth, attributed to the combined abrasive–delamination resistance of TiC and Nano-sized Al 2 O 3 . However, reinforcement beyond 5–7 wt.% induced particle clustering, degrading mechanical properties due to stress concentration and brittle fracture mechanisms.