Nb微合金化低合金钢在模拟深海环境下断口形貌:不含Nb钢在(a1)空气中;(b1)5Mpa压强,3.5%氯化钠溶液中;(c1)10mA/cm2的充氢电流预充氢10h后,在5Mpa压强,3.5%氯化钠溶液中;Nb钢在(a2)空气中;(b2)5Mpa压强,3.5%氯化钠溶液中;(c2)10mA/cm2的充氢电流预充氢10h后,在5Mpa压强,3.5%氯化钠溶液中;
SEM images of the fracture surfaces of the (a) Nb-free and (b) Nb-bearing steels in air (a1, b1) and at charging current densities of 0 mA/cm2 (a2, b2) in 3.5 NaCl solution at 5MPa and 10 mA/cm2 (a3, b3) in 3.5 NaCl solution at 5MPa.