Free expansion and irreversible expansion

[Sue Xu 2K]

Is the term "free expansion" the same as irreversible expansion?

[Mitch Walters]

I believe free expansion is when there is no opposing pressure on a system, so it is allowed to expand without doing any work. Irreversible expansion is what allows for the maximum amount of work.

[Jenny Cheng 2K]

No work is done in free expansion; an example of free expansion is a gas pushing against a piston and into a vacuum. Free expansion is an irreversible process, but it is not the same as irreversible expansion. For an irreversible expansion, P(external) does not equal P(internal).
Reversible expansion allows for the maximum amount of work to be done because P(external) equals P(internal).