Determined to like an alloy (6)
I believe the answer is:
steely
'determined' is the definition.
(I've seen this before)
'like an alloy' is the wordplay.
I cannot quite see how this works, but
'like' could be 'ly' (similar in meaning) and 'ly' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for steely that I've seen before include "Set off" , "As hard, or grey, as metal" , "Strong" , "Gimlet-eyed" , "Hard and metallic" .)