Structural investigations of nanocrystalline Ti-Al and Ni by PAC

Nanocrystalline Ti-Al and Ni are investigated on an atomic scale by perturb ed angular correlation spectroscopy in combination with X-ray diffraction. Ti-Al compounds produced by mechanical alloying consist of disordered solid solutions. Annealing of the samples effects a transformation into ordered intermetallic compounds, which is observed via the occurrence of characteri stic electric field gradients. The local magnetic properties of nanocrystal line Ni, produced by pulsed electrodeposition, are investigated. Besides th e local magnetic field known from polycrystalline Ni, a second component is detected, which is attributed to a magnetic perturbation due to grain boun daries. The width of this magnetic boundary is estimated to 3-4 nm.