also known as vs alias

also known as is not a noun while alias is a noun.

Word	Noun	Adjective	Verb	Adverb
also known as	No	No	No	Yes
alias	Yes	No	No	Yes

As adverbs, also known as and alias are synonyms defined as:

Other synonyms of also known as include a.k.a..

also known as (noun)	alias (noun)
	a name that has been assumed

also known as (adverb)	alias (adverb)
as known or named at another time or place	as known or named at another time or place