Electron Diffraction of ThMn12/Th2Zn17-Type Structures in the Nd-Fe-Ti System

Nd:11Fe:Ti alloys prepared by arc melting followed by splat quenching and annealing have been investigated by electron microscopy. The as-cast microstructure evidenced an alpha-Fe(Ti) -> NdFe11Ti -> Nd-2(Fe,Ti)(17) solidification sequence compatible with a cascade of peritectic reactions. The Nd-2(Fe,Ti)(17) phase was not detected in the microstructure of the splat-quenched materials, but after annealing the ternary compound grains consisted of a mixture of ThMn12-type and Th2Zn17-type structures exhibiting a consistent (020)(1:12)//(003)(2:17) and [100](1:12)//[110](2:17), orientation relation, with the invariant plane sitting at (022)(1:12)//(3N33)(2:17). A series of 3D microdiffraction experiments carried out on grains presenting a random distribution of planar defects has been used to map the reciprocal space of the intergrown phases.