Densification behaviour of sintered aluminum composites during hot deformation

Abstract

In this study, an investigation on the densification behavior and forming limit of powder metallurgy composites containing hard carbide particles were carried out. The selected composite materials are Al4TiC, Al4WC, Al4Fe3C and Al4Mo2C. The compacts of 0.82 and 0.86 relative density and 0.4 and 0.6 aspect ratio were prepared on a 1-MN capacity hydraulic press using suitable die-set assembly. Sintering was carried out at 594 ℃ for 60 minutes in an electrical muffle furnace. Hot upsetting was carried out at the sintering temperature immediately after the sintering process and the forming process was stopped once visible cracks were seen on the free surface. Flat dies on the upper and lower surface were employed under dry friction conditions during hot upsetting. Finally, the densification behavior and forming limit of sintered-forged aluminium composite preforms is presented in this research work. It was concretely noted that Al4TiC produced the best density amongst all the above mentioned aluminium composites. Further, it was seen that Al4Mo2C and Al4WC produced good final height and diameter strain at fracture.

Keywords

• densification
• forming limit
• aluminium composite
• hot forging
• powder metallurgy