Shallow cryogenic treatment: effect on the corrosion resistance and hardness properties of AA5083-H111 alloy in chloride-ions enriched medium

Abstract

The influence of cryogenic and cryogenic time (10, 24, 36, 48, and 72 h) on the hardness, surface roughness, and corrosion resistance properties of AA5083-H111 alloy in 3.5 wt.% NaCl solution have been investigated. The hardness property was analysed via the Brinell hardness measurement, the corrosion resistance property was measured electrochemically, while the morphological studies were undertaken using the SEM (scanning electron microscopy) and atomic force microscopy (AFM). The results disclose that the shallow cryogenic treatment at −80°C improves the alloy’s hardness, surface roughness, and the corrosion resistance. The best cryogenic treatment time is 24 h. Cryogenic treatment for 24 h increases the alloy’s hardness from 71.3 HB to 74.90 HB, reduces the average surface roughness from 534.000 nm to 105.634 nm, and increases the total charge transfer resistance from 18139 Ω cm ^2 to 26230 Ω cm ^2 . The improvement is linked to settling of fine particles on the alloy surface. The SEM results support these claims.

Keywords

• aluminium alloy
• cryogenic treatment
• cryogenic time
• hardness
• corrosion resistance
• roughness