Al-Cu Solidification Cracking Susceptibility

⚠ Disclaimer: Use at Your Own Risk This tool is provided "as is," for general engineering reference and educational purposes only, with no warranty of any kind. It uses a simplified binary Al-Cu model: a linearized liquidus (pure Al at 660.3°C to the eutectic at 33.0 wt% Cu / 548°C), a constant partition coefficient (k = 0.17), and the Scheil equation (no solid-state diffusion, complete liquid mixing) to generate the solidification path, terminated by an isothermal eutectic reaction. The cracking susceptibility index follows S. Kou, "A criterion for cracking during solidification," Acta Materialia 88 (2015) 366–374, defined as the maximum local steepness of the T–√fs curve, found up to Kou's √fs = 0.99 evaluation limit. This is exactly as shown in his own worked figure for 6061/2219/2014/2024/7075, where a short tangent is fit to the steepest part of each curve, always short of the flat eutectic plateau since a flat segment can never contain the maximum. The result is then compared against the classic hot-shortness curves of P.H. Pumphrey & J.V. Lyons (1948). Real Al-Cu alloys deviate from a linear liquidus and constant k, especially above a few wt% Cu, and actual cracking depends heavily on restraint, grain structure, and impurities not modeled here. Jeffrium and Jeffrey Sowards assume no liability for decisions, designs, procedures, or outcomes based on this tool's output. Do not use these results as the sole basis for alloy selection or procedure qualification; verify independently. Use of this tool is entirely at your own risk.