Metallic mixtures or all-soy mixture? (6)
I believe the answer is:
alloys
'metallic mixtures' is the definition.
(I've seen this in another clue)
'all-soy mixture?' is the wordplay.
'mixture?' indicates anagramming the letters (I've seen 'mixture' mean this).
'soy' anagrammed gives 'oys'.
'all'+'oys'='ALLOYS'
'or' acts as a link.
(Other definitions for alloys that I've seen before include "Metals formed from mixtures of other metals" , "Tempers" , "Puts down" , "Blends of metals" .)