Advanced heat treated die-cast aluminium composites fabricated by TiB2 nanoparticle implantation. (15th January 2020)

• Record Type: Journal Article
• Authors: Dong, Xixi; Youssef, Hamza; Zhang, Yijie; Yang, Hailin; Wang, Shihao; Ji, Shouxun
• Is Part Of: Materials & design. Volume 186(2020)
• Publication Date: 2020-01-15
• Subjects: Aluminium alloy -- High pressure die casting -- Super vacuum -- Nano reinforcement; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2019.108372
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: The global carbon emission reduction strongly requires high strength lightweight die-cast aluminium alloys in industry. Here die-cast AlSiMgMn–TiB2 composites with advanced mechanical performance were fabricated by the implantation of TiB2 nanoparticles. Super vacuum assisted high pressure die casting was applied to enable the T6 heat treatment of the composites, and the super vacuum of 20 mbar was achieved in the limited evacuation time of 1.6 s. The composites demonstrated good die castability within the addition of 3.5 wt% TiB2, while the composites could not fill into the chill vent with the addition of >3.5 wt% TiB2 . The composite with 3.5 wt% TiB2 nanoparticles delivered the high hardness of 150.2 kg/mm 2, yield strength of 351 MPa, tensile strength of 410 MPa, and the industrially applicable good ductility of 5.2%, after T6 heat treatment. The strengthening of the T6 heat treated composite was a result of both TiB2 nanoparticles and nanoscale β′′ precipitates that had coherent interfaces with α–Al matrix, i.e., Al(11-1)//TiB2 (0001), Al[011]//TiB2 [11-20], Al[320]//β″( a -axis), Al[1-30]//β″( c -axis) and Al(020)//β″( b -axis). The T6 heat treated composite reinforced by 3.5 wt% TiB2 showed ductile fracture. Graphical abstract: Unlabelled Image Highlights: Super vacuum of 20 mbar was achieved in limited evacuation time of 1.6 s during die casting of AlSiMgMn/TiB2 composites. Heat-treated AlSiMgMn/3.5wt.%TiB2 composite had yield strength of 351MPa, tensile strength of 410MPa and ductility of 5.2%. Die castability of compsites decreased with increasing of TiB2 nanoparticles due to decrease of die filling ability. Strengthening of heat-treated AlSiMgMn/TiB2 composites resulted from TiB2 nanoparticles and β′′ precipitates.