Let me answer your question indirectly. Most copyright agreements with most publishers have the clause that cautions the author from distributing the material without seeking permission from the publisher without which it will be considered violation of the copyright law. Before you post your journal publications, consult your journal publisher.
If it is NOT an Open Publication journal, you usually cannot distribute THEIR version. Many journals allow you to post a "pre-publication" version, such as the final version you sent to the journal. I have done this several times.
But as Sam and Charles say, every journal is different and you must look at the journal's policy, which should be on their website.