This study deals with the mechanical characterization of materials resulting from Markforged Atomic Diffusion Additive Manufacturing (ADAM) process. 17-4PH stainless steel fabricated by ADAM was investigated by exploring the microstructure generated by this manufacturing process, then analysing the effect of the microstructure on the deformation of such materials. Single Edge Notch Tensile (SENT) 17-4PH samples were fabricated in order to highlight microstructure effects in in-situ tensile tests. Then, a microscale experimental method coupled with digital images correlation (DIC) was used to measure kinematic fields of the sample surface. The effect of the deposited layer thickness on the material deformation was investigated by testing two samples fabricated with the same printing parameters except the layer thickness (i.e., 50 µm and 125 µm filament diameter). The results show that the layer thickness is an important printing parameter for such process since it affects the measured kinematic fields.