High performance Al/TiB2 composites fabricated by nanoparticle reinforcement and cutting-edge super vacuum assisted die casting process

Abstract

The structural lightweight in automotive and other industries motivates the usage of high strength die-cast aluminium alloys. However, the improvements of die-cast aluminium alloys are struggling limited by conventional micro alloying, and the improved yield strengths are still in the low level of 180–190 MPa. Here, high performance die-cast AlSiMgCu/TiB2 composite was fabricated through the reinforcement of TiB2 nanoparticles and the latest developed cutting-edge super vacuum assisted high pressure die casting (HPDC) process. The composite with 3.0 wt% TiB2 nanoparticles could deliver the milestone high hardness of 1.56 GPa, yield strength of 356 MPa, tensile strength of 457 MPa and an industrially applicable ductility of 5.5%. The composite was strengthened by TiB2 nanoparticles and nanoscale Q′ and θ′ precipitates that all had highly coherent interfaces with the α–Al matrix, indicative of strong interfacial bonding. The implantation of TiB2 nanoparticles also induced special grain refinement strengthening of the composite. The fabricated composite demonstrates ~90% increase in strength over the currently available alloys, and it is promising for industrial application.