Effect of Double Thermal Ageing Treatment on the Hardness and Corrosion Resistance of Al- Cu- Si- Ni Alloy in NaCl Solution

Abstract

This work investigated the Corrosion behavior and hardness characteristics of double thermally treated Al-Cu-Si-Ni alloy in NaCl solution. The alloy was produced using sand casting method, and sectioned into small pieces of 10mm long each. Some of the sectioned samples were subjected to single thermal ageing treatment (STAT) and used as control, while others were subjected to double thermal ageing treatment (DTAT). The thermally treated samples were used for corrosion and hardness test in accordance with ASTM A370 and ASTM E8-08b. The result showed that the double thermally treated samples have higher hardness value than the single thermally treated samples as the ageing time increases with an increase of 24.6% at 2hrs. Equally, the corrosion resistance of the treated alloy improved with ageing time.