Mastering of Metal Solidification

Defects in metals originate from the microstructure. Often during solidification processes, especially in refractory metals, defects, voids, and gas bubbles can form. Could we just by looking at the surface understand in-depth defect formations, and possibly mitigate them? Conventional wisdom says no, but an experienced veteran welder can tell you if a weld is bad by only working from the surface. We would combine information from x-ray, optical techniques, and process parameters, to correctly inform an AI to be our veteran welder, able to say if there are voids, gas bubbles, or other defects under the surface in your material.