Effect of Multidirectional Forging and Heat Treatment on Mechanical Properties of in Situ ZrB2p/6061Al Composites

Abstract

Aluminum matrix composites that were reinforced by in situ zirconium diboride nanoparticles were fabricated from an aluminum-potassium tetrafluoroborate-potassium hexafluorozirconate system via a direct-melt reaction. The morphologies of the in situ particles and the mechanical properties of the composite were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractometry, optical microscopy and tensile tests. X-ray diffractometry and energy-dispersive X-ray spectroscopy showed the existence of zirconium diboride in the composite. Multidirectional forging and heat treatment were used to determine the effect of plastic deformation and heat treatment for the highest tensile strength applied to the composite. Multidirectional forging and heat treatment have a positive influence on the composite microstructure and tensile strength, which increase by 21.81 % and 13.43 %, respectively. The mechanism of multidirectional forging and heat treatment that affects the composite mechanical properties has been discussed. The heat-treatment parameters that affect the tensile strength include the solution-treatment temperature, aging temperature and aging time. The highest tensile strength with moderate extensibility loss was achieved for a specimen that was solution treated for 4 h at 793 K and with aging at 423 K for 4 h.