Effect of interaction between hydrogen and intermetallic compound particles on stress corrosion cracking behavior of 2050 aluminum alloy

The effect of interaction between hydrogen and intermetallic compound particles (IMPs) on the stress corrosion cracking (SCC) behavior of 2050 aluminum alloy was studied. With the hydrogen charging potential decreased from -500 to -1000 mV_OCP, SCC sensitivity indices of alloys increased from about 15.2% to 54.5%. The crack initiation and propagation process of SCC of the alloy in environments affected by hydrogen was dominantly controlled by HFAD and HEDE mechanisms, respectively. In the crack initiation process of SCC, hydrogen was preferentially accumulated around AlCuMnFe IMPs with low content of Cu to form the hydrogen-affected zone with the Volta potential lower than that of the matrix, resulting in the accelerated pitting initiation and crack initiation. In the crack propagation process of SCC, the aggregation of hydrogen at grain boundaries reduced atomic binding energies, leading to rapid crack propagation along the grain boundaries.