Yes, Robert Downey Jr has used the same stunt double for all the films where he plays the Iron Man character, including the new Avengers film. In another recent film, the new Sherlock Holmes movie, Downey did most of his own stunts.

The stuntman's name is Clay Fontenot, and he has worked in more than 50 movies, for famous directors like Quentin Tarantino. Another stuntman, Jeremy Fitzgerald, was lately injured while filming the Avengers, though he went back to work the same day.

A stunt performer has one of the hardest jobs in show business. They have to be super fit, the work can be dangerous and quite often the pay isn't very good either. At the same time, it's a very exciting life and the stuntman knows how valuable he is; movies wouldn't be nearly as good without them.