(a) Corrosion product buildup over a lack of fusion pore in SLM 17-4 PH after 7 d immersion in quiescent 0.6 M NaCl and (b) anodic polarization behavior of the same material in 0.6 M NaCl using a microelectrochemical cell over areas with (>50 μm) and without (<10 μm) lack of fusion pores compared to wrought 17-4 PH. Reprinted from Schaller, et al.¹⁰¹