hardened vs tempered

hardened and tempered both are adjectives.

Word	Noun	Adjective	Verb	Adverb
hardened	No	Yes	No	No
tempered	No	Yes	No	No

As adjectives, hardened and tempered are synonyms defined as:

hardened and tempered: made hard or flexible or resilient especially by heat treatment

Other synonyms of hardened include toughened, treated.

hardened (adjective)	tempered (adjective)
made hard or flexible or resilient especially by heat treatment	adjusted or attuned by adding a counterbalancing element
protected against attack (especially by nuclear weapons)	made hard or flexible or resilient especially by heat treatment
made tough by habitual exposure
converted to solid form (as concrete)
used of persons; emotionally hardened