Structural development during mechanical alloying of crystalline niobium and tin powders

1089-7550

AIP Digital Archive

Physics

The structural development with milling time during mechanical alloying of niobium and tin powders, of average composition Nb3Sn, was followed by x-ray diffraction. The elemental powders initially alloy mechanically to form an A15 structure phase. With continued milling, the A15 phase transforms to an amorphous structure. The kinetics of the structure changes are dependent on the milling media and atmosphere. The measured lattice parameter a0 for the A15 phase prepared with tungsten carbide milling media in an argon atmosphere agrees with the literature value of a0 for bulk Nb3Sn. However, milling with steel media introduced significant contamination by iron and an anamolous expansion of the A15 phase lattice. Amorphization of the A15 phase is believed to be due to the creation of a critical defect concentration by the mechanical deformation.

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