Manipulation of thermal and mechanical stability by addition of multiple equiatomic rare-earth elements in Al-TM-RE metallic glasses

In the present study, we demonstrate that the addition of multiple equiatomic rare-earth elements (REs) in the order of electronegativity in Al 84 Ni 10 RE 6 (RE = La, Ce, Nd, Gd, Y) metallic glasses (MGs) can result in stabilizing supercooled liquid region and destabilizing shear avalanches via controllably induced compositional complexity. In detail, the addition of multiple equiatomic REs leads to a relatively fragile glass, but interrupts easy crystallization behavior in Al 84 Ni 10 (LaCeNdGdY) 6 MG, which causes a larger supercooled liquid region and higher thermoplastic formability. Furthermore, the increased structural instability reduces cut-off size of self-organized shear avalanches and increases the number of chaotic shear avalanches, which can distribute the applied strain more homogeneously, resulting in enhanced intrinsic ductility. These results provide a guideline on how to design promising Al-based MGs with high thermal stability and improved mechanical stability, which is a key step to developing ductile Al-based bulk metallic glasses through thermoplastic forming process.