I have some duets for cello and violin. Can the flute play the parts written for the violin in the treble clef?

yes you can but there are somethings you will have to look out for like any notes below middle c

during the middle ages, renaissance and baroque periods, most parts were interchangeable, or were for C instruments

Piano, violin, flute, guitar, mandolin, some old saxophones, oboe and recorders are all in key of C. So you can interchange all sheet music from these instruments without being off key.
It is also important for players who have been playing for awhile to learn to transpose, that is playing music from an odd key to sound in tune. Transposing is not for beginners, it is pretty complex, but very useful.

Thanks, everyone. We`ll give it a try. (My daughter plays flute and I play cello.) I have a book with easy duets for cello and violin, but I haven`t been able to find any music on that level for cello and flute.

Donna

I forgot cello, upright bass, and maybe Viola are also in C I am pretty sure.
I have learned flute duets on my guitar and piano since they can play more than one note. You can reallly try interesting stuff. Like using piano music and having the cello play the bass notes and flute on higher ones. Be creative in your personalized arrangments of music It will probably sound good and unique.
I have a book I only use for guitar and its Mozarts piano sontas, many are not really hard on guitar and its fun.

1234567,
Thanks for the idea of using piano music with flute playing treble clef and cello playing the bass. That should work well with the Bach and Mozart minuets that I have for piano.
Donna