Development of high strength AA 7010 aluminum alloy resistant to environmentally assisted cracking

• The new heat treatment (SA 20) raised UTS values by ∼10% in relation with over aged alloy in 3.5 wt.% NaCl.
• Due to the change in heat treatment (SA 20) the ductility of the alloy increased from 12% to 14% in 3.5 wt.% NaCl.
• Coarser grain boundary precipitates with higher Cu content imparted the resistance.

An attempt has been made to develop AA 7010 having significantly high strength and resistance to environmentally assisted cracking in 3.5 wt.% NaCl. By tailoring heat treatment based on the secondary aging concept, strength levels equaling peak aged condition and environmentally assisted cracking resistance exceeding conventional over aged condition has been obtained. Coarser and discontinuous network of grain boundary precipitates with higher Cu enrichment than even over aged alloy have led to this beneficial effect.