Intergranular Corrosion of Cryorolled and Aged D16 Aluminum Alloy

Abstract

Structural and phase factors influencing the intergranular corrosion (IGC) of D16 aluminum alloy after quenching, isothermal rolling at liquid-nitrogen temperature, and subsequent natural and artificial aging were studied by optical metallography, X-ray diffraction, and transmission and scanning electron microscopy. It is established that the alloy aged at temperatures below 150°C demonstrate low depth and intensity of corrosion attack, which sharply increase with aging temperature up to 190°C. The alloy behavior is caused by the accelerated decomposition of the preliminary supersaturated aluminum solid solution, accompanied by formation of the mixed structure of the matrix with a bimodal distribution of main strengthening phases. It is concluded that IGC of the cryorolled and aged alloy has an equal nature and mainly caused by phase factors.