Investigation of the free volume change of Fe41Co7Cr15Mo14C15B6Y2 bulk metallic glass using the cyclic thermal dilatation test

► Free volume change in cyclic heating is studied by the cyclic thermal dilatation test. ► Sample diameter and pre-annealing effects on the free volume changes are investigated. ► A free volume generation peak occurs in glass transition after 2 hours pre-annealing. ► Kohlrausch exponent of Fe41Co7Cr15Mo14C15B6Y2 BMG obtained by cyclic DIL test is 0.34.