Can i say "sallallahu alayhi wa sallam" instead of the dorud e ibrahim? in the salah after the tashahud, in the final sitting.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

The minimum sufficient form of sending blessings upon the Prophet in Prayer according to the scholars who say that it is obligatory, it is to say: “Allaahumma Salli ‘ala Muhammad.” (O Allah! Bestow your Blessings and Peace upon Muhammad.), and other wordings like "Sallallaahu ‘ala Muhammad"; this is what the Shafi’i and Hanbali jurists mentioned and they say it is obligatory in prayer. In addition, they stated that it is not enough to say: "Sallallaahu 'alayhi" as pronoun (without mention of his name). Based on this, it is not sufficient in prayer to say: “” independently without mentioning his name or without describing him as a Prophet and a Messenger.

For more benefit on the shortest form of Tashahhud and its different wordings, please refer to Fatawa 371557, 322516 and 375343.

Allah knows best.