Chemical ordering around open-volume regions in bulk metallic glass Zr52.5Ti5Al10Cu17.9Ni14.6

We provide direct experimental evidence for a nonrandom distribution of ato mic constituents in Zr52.5Ti5Al10Cu17.9Ni14.6 bulk metallic glass using pos itron annihilation spectroscopy. The Ti content around the open-volume regi ons is significantly enhanced at the expense of Ni and Cu. Our results indi cate that Ni and Cu atoms closely occupy the volume bounded by their neighb oring atoms while Al, Ti, and Zr are less closely packed, and more likely t o be associated with the open-volume regions. The overall distribution of e lements seen by the positron is not significantly altered by annealing or b y crystallization. Theoretical calculations indicate that the observed elem ental distribution is not consistent with the known crystalline phases Zr2C u and NiZr2, while Al3Zr4 shows some of the characteristics seen in the exp eriment. (C) 2000 American Institute of Physics. [S0003-6951(00)05139-1].