I teach my younger brother gemara Brachos. Can we make a siyum on one perek (one that can even be matir meat on the nine days)?
In order to make a siyum the person has to finish a whole mesecheta, a seder mishnayos, a whole sefer of tanach, etc. but not if it is only part of a mesecheta.
Nevertheless, it is still a simcha and you can have a special supper etc., (just not fleishigs) to celebrate this great accomplishment.
Rema O:CH 551-10, Kovetz Halachos ( Horav S. Kaminetzsky shlit”a ) Bein Hametzrim pg. 127.