DEFORMATION PROCESSING OF ALUMINIUM ALLOY 2618. PART II: DEVELOPMENT OF A PROCESSING MAP.

Aluminum alloy 2618 (RR 58) which has been processed by in-situ upset forging is analyzed for its mechanical properties as well as microstructure. The particles in the matrix are found to dissolve at high temperatures. The ductility of the upset forged product exhibits maximum ductility in the temperature range 500 to 650 K. A high-temperature treatment above 600 K followed by fairly rapid cooling gives solid-solution strengthening in the alloy at room temperature. Based on the mechanical properties and microstructure of the product, a processing map has been developed, and a 'safe' window in the strain rate - temperature field has been identified, isolating the regimes of cavity formation at the matrix - particle interface and wedge cracking at the grain boundaries.