The Jominy End-Quench Test for Investigation of Corrosion Properties and Microstructure of High Strength Aluminum Alloys

摘要

The Jominy test was applied to extruded rods of aluminum alloys 2024 and 7075 in order to obtain a decreasing quench rate over the length of the rods. The alloys were heat treated to the conditions 2024-T4, 2024-T6, and 7075-T73. The relation between quench rate, corrosion properties, and microstructure is discussed. Stress corrosion crack (SCC) initiation tests reveal that 7075-T73 is completely immune to SCC; 7075-T6 is sensitive to SCC for a cooling rate higher than 15 K/sec and 2024-T4 and 2024-T6 has low stress corrosion resistance for all cooling rates. The high stress corrosion resistance mentioned in the literature for fast quenched 2024 alloys is not confirmed. Exfoliation corrosion tests show that fast quenched parts of the 2024-T4, and 7075-T6 and 7075-T73 rods are reasonably resistant to intergranular corrosion. Stress corrosion resistance is improved by producing incoherent precipitates.