Determination of critical cooling rates in metallic glass forming alloy libraries through laser spike annealing.

ABSTRACT: The glass forming ability (GFA) of metallic glasses (MGs) is quantified by the critical cooling rate (R _C). Despite its key role in MG research, experimental challenges have limited measured R _C to a minute fraction of known glass formers. We present a combinatorial approach to directly measure R _C for large compositional ranges. This is realized through the use of compositionally-graded alloy libraries, which were photo-thermally heated by scanning laser spike annealing of an absorbing layer, then melted and cooled at various rates. Coupled with X-ray diffraction mapping, GFA is determined from direct R _C measurements. We exemplify this technique for the Au-Cu-Si system, where we identify Au₅₆Cu₂₇Si₁₇ as the alloy with the highest GFA. In general, this method enables measurements of R _C over large compositional areas, which is powerful for materials discovery and, when correlating with chemistry and other properties, for a deeper understanding of MG formation.

SUBMITTER: Bordeenithikasem P 

PROVIDER: S-EPMC5540923 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature