Влияние ионного облучения на морфологию, элементный и химический состав поверхностных слоев безвольфрамовых твердых сплавов

The effect of ion beams with different intensity and duration on the change in the elemental composition and chemical state of the tungsten-free hard alloy (50% TiC - 50% TiNi) surface layers has been investigated. The analysis of the morphology and composition of the hard alloy surface layers after both exposure to continuous and powerful ion beams was carried out by scanning electron microscopy and X-ray photoelectron spectroscopy. It is shown that irradiation with a continuous ion beam causes additional oxidation of the hard alloy surface. It was found that the impact of the powerful ion beam leads to a decrease in metal oxides amount and the formation of titanium carbides in the intermetallic binder phase (TiNi) of the hard alloy.

Evolution of Structural-Phase States in TiNi Surface Layers Synthesized by Electron Beam Treatment

The paper presents the results of X-ray diffraction analysis of nonequilibrium structural and elastic stress states in TiNi surface layers irradiated by low-energy electron beams. It is found that a surface layer with a mixed (2D columnar and 3D equiaxial) submicrocrystalline structure is formed on the irradiated side of the TiNi specimens, and the volume fractions of the two structure types depend on the beam energy parameters and number of pulses. The B2 phase synthesized in the layer is characterized by lattice microstrain due to stresses of the first and second kinds (εI≈±1%,εII=0.25%), and the layer as such is an internal stress concentrator for underlying layers of the material. In the intermediate layer beneath the stress concentrator, relaxation of irradiation-induced internal stress takes place. It is shown that the main mechanism of the relaxation is partialB2→B19′martensite transformation. TheB19′martensite phase in the intermediate layer decreases the microstrain in the conjugate B2 phase. The thickness of the layer in which the relaxation processes develop through theB2→B19′martensite transformation is 10–15μm.