SUPERPLASTIC FORMING & DIFFUSION BONDING

Superplastic Forming & Diffusion Bonding (SPF/DB) Vector Prepress Guide

Superplastic Forming combined with Diffusion Bonding (SPF/DB) enables single-operation fabrication of complex hollow monolithic titanium aerospace structures with internal truss reinforcements, slashing airframe weight and eliminating thousands of mechanical fasteners.

1. High-Temperature Superplasticity & Solid-State DB

Titanium alloy Ti-6Al-4V exhibits superplastic behavior at 900°C under high vacuum. Solid-state diffusion bonding joins atomic lattice planes under 3–5 MPa pressure, followed by pressurized argon gas injection that superplastically inflates the internal core into hollow truss or honeycomb geometries.

2. Engineering Specifications & Tolerances

3. Stop-Off Stencil Vector DXF Prepress Specifications

• Stop-Off Land Width Tolerance: Silk screen stencil patterns for Yttria stop-off ink must maintain $\pm 0.15\text{mm}$ line width tolerance to ensure accurate diffusion bond land widths.
• Argon Gas Manifold Passages: Incorporate continuous $1.5\text{mm}$ stop-off vector runners connecting all internal expansion cells to the central gas injection inlet port.
• Thermal Expansion Die Offset: Tooling cavity DXF dimensions must scale by $+0.92\%$ to compensate for thermal expansion differences between INCONEL 718 hot press dies and the titanium pack at 900°C.