The effect of hydrogen charging on the mechanical properties of leaded α/β brass cast alloy

At the present work, the effect of the cathodic charging on the mechanical properties of leaded α/β brass cast alloy was investigated. The charging conditions of the test samples were as follows: current density: (a) 5 mA/cm2, (b) 20 mA/cm2, (c) 40 mA/cm2 and (d) 55 mA/cm2. The durations of the charging of the test samples were (a) 5 h, (b) 10 h, (c) 15 h, (d) 25 h and (e) 50 h. For the samples that underwent tensile stress at three different rates of loading, the following conditions of hydrogen cathodic charging were selected: current density: 20 mA/cm2 with charging time of (a) 5 h, (b) 20 h and (c) 40 h. All of the samples were subjected to tensile stress tests with a constant deformation rate of 10−4sec−1. The main conclusions for the above investigation are that the average value of the microhardness of the surface of the cathodically charged test samples was found to increase with the increase in the current density of cathodic charging at a constant value of cathodic charging time and with the increase of the cathodic charging time at a constant value of current density, in addition to an decrease of the microhardness value of the cathodically charged test samples with increased distance from the test sample's surface. The maximum width of the affected area, under the conditions of the experiment, was 550 μm. The ductility of the cathodically charged test samples was notably reduced compared to that of the uncharged material, compared to the uncharged material.