Morphological and structural changes of sintered Cu-10 wt% Al materials with different alloying levels in salt spray environment

Morphological and structural changes of spark plasma sintered Cu-10 wt% Al materials in salt spray environment were studied. The tested materials possessed the same elemental composition but different phase compositions (Cu-Al composite, Cu(Al) solid solution and Cu-Cu(Al)-Cu9Al4 alloy). The oxide films formed on the surface of the corroded samples were confirmed to be enriched with Al. The subsurface regions of the Cu-Al composite and Cu (Al) solid solution did not reveal any microstructural changes after the salt spray test. When the Cu-Cu(Al)Cu9Al4 alloy corroded, the aluminum contained in the alloy oxidized such that the oxide particles formed both on the surface of the sample and in the subsurface region. While the Cu-Al composite and Cu(Al) solid solution maintained integrity, the Cu-Cu(Al)-Cu9Al4 alloy experienced swelling and cracking during the salt spray test.