'aluminum-composed' is a compound formed from the noun 'aluminum' + the past participle 'composed' (from 'compose', meaning 'put together').

'Aluminum' ultimately traces to Latin 'alumen' (alum); the modern English name was shaped in the early 19th century as 'aluminium' and later shortened in American usage to 'aluminum'. 'Compose' comes from Latin 'componere' via Old French and Middle English, yielding the past participle 'composed'.

Originally, 'compose' meant 'to put together'; when combined with a material name it has come to be used simply as an adjectival descriptor meaning 'made of' that material—so 'aluminum-composed' now straightforwardly means 'made of aluminum'.