We can see that the stress is zero directly above the support at the end. The stress is highest directly under the load. Assuming there is no yielding, there will be a linear increase of stress with distance as we approach the position in dead center. Note also that if the location of interest is above the neutral axis, the stress will be compressive. If it is below the neutral axis, it will be tensile. This is commonly addressed by assigning one of the stresses (usually compressive) a negative sign. We won’t worry about this any more than to say that you have to look at the absolute values of these normal stresses when comparing to the strength values, to determine if the stress has exceeded the strength.
So, there is the inner core, 7 inches thick that has NOT yielded! Therefore, as a gross oversimplification that you should use conceptually to understand what is happening, and not assume you can do a similar calculation to make a safely designed object (because this would be a bad idea), the beam is deflected, but since there is an unyielded core, if the load were removed, it would partially return toward its original shape.
Next time, we will bring case hardening more fully into the discussion.