Iron Man’s sentient armor creates an AI version of Professor Sun Tao—a former cult leader—and this leads to a lot of Iron Man vs other armors stuff until we learn the real villain is Ultron. The new AI life form sides with Tony, Ultron is defeated, and the sentience is put into an organic child body.
This is a pretty boring arc. Ultron is supposed to be ultra-badass. His threat level is lessened he gets involved with a sentient armor that just wants to be a real boy, and lets himself get beaten by a single Avenger.
Note: #46 is a 100-page “monster” issue that has a bunch of reprints in it in addition to the first installment of the above story arc.