An effective joint of continuous SiC/Ti-6Al-4V composites by diffusion bonding

Abstract

The continuous SiC/Ti-6Al-4V composite was fabricated through a hot pressing procedure. Solid state diffusion (SSD) and transient liquid phase (TLP) bonding processes were applied to join continuous SiC/Ti-6Al-4V composites to a Ti-6Al-4V plate and to themselves. The butt joint strength of the composite to the Ti-6Al-4V plate reached a maximum of approximately 850 MPa for V_f = 30% composite. The maximum strength is 90% of the tensile strength of the Ti-6Al-4V alloy. When the composite was bonded directly to itself, a sound joint was not obtained. A joint strength equal to composite Ti-6Al-4V's joint strength was obtained using Ti-6Al-4V and Ti-Cu-Zr thin foils as filler metal. However, a fracture occurred not at the base metal but at the bonding interface.

Scarf joint forms were also used to join a composite to a Ti-6Al-4V plate and to itself. When the scarf angle was less than 12°, the composite-composite joint strength reached a maximum value of 1380 MPa corresponding to 80% tensile strength of the base material. The composite-composite scarf joint was fractured at base material. The composite-Ti-6Al-4V scarf joint was also fractured at the Ti-6Al-4V plate when the scarf angle was less than 12°. It is possible to join the SiC/Ti-6Al-4V composite without any reinforcing parts, such as a doubler.