Aluminum bronzes, dealuminification

Dealuminification Aluminum (Al) leached from aluminum-bronzes... 

Dealuminification occurs in aluminum bronzes containing the y-2 phase microstructure and the process is more severe when the y-2 phase forms a continuous grain boundary network. Dealuminification can be averted by rapid cooling from >600°C, or by addition of 1-2% iron or more than 4.5% nickel. Microstmctural changes can still occur during welding and lead to corrosion in the heat-affected zone. 

A corrosion mechanism similar to brass dezincification, known as dealuminification, can occur to the beta phase or eutectoid structure depending on environmental conditions. Proper quench and temper treatments produce a tempered beta structure with reprecipitated acicular alpha crystals, a combination often superior in corrosion resistance to the normal annealed structure. The nickel component in the more complex nickel aluminum bronzes alters the corrosion characteristics of the beta phase because of the nickel additive and gives greater resistance to deaUoying and cavitation-erosion in most liquids. 

Aluminum bronzes Hydrofluoric acid, acids containing chloride ions Aluminum (dealuminification)... 

---