Lattice Location of Boron and Hafnium Dopants in an Aluminide by Use of Ion Channeling/Nuclear Reaactnio Analyses

Abstract

AbstractExperiments have made use of Rutherford backscattering (RBS), ion channeling techniques and analyses for nuclear reaction products to study lattice location of B and Hf dopantsin an ordered nickel aluminide. Studies were of an alloy single crystal of composition Ni76A123Hf1 with about 0.1 at. % of B added. Analysis for B was accomplished by detection of alpha particles resulting from the reaction 11B(p,αi)8 Be, in ion channeling experiments in which RBS from the Ni constituent was used to control channeling in the host lattice. Yield of the reaction product from proton interaction with B decreased relative to random for channeling in a <100> direction, but increased relative to random for channeling in a <110= direction. It was concluded that B occupies primarily octahedral interstitial sites. RBS/channeling half-angles for Hf in a <100> direction are somewhat smaller than those for Ni, but nevertheless considerably larger than half-angles expected for Al. It is concluded that the majority of Hf atoms are on the Ni sublattice.