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

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 theta' precipitates that all had highly coherent interfaces with the alpha-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 similar to 90% increase in strength over the currently available alloys, and it is promising for industrial application.