| Abstract: |
On commercially pure Al substrate, titanium and niobium films were deposited by DC magnetron sputtering(MS), followed by electron beam treatment (EBT) with scanning electron beam. EBT was carried out on the ESW300/15-60 units manufactured by Leybold-Heraeus. The technological parameters of the EBT process were the following: accelerating voltage 60kV; beam current from 35 to 55 mA, speed movement (alloying speed) of Al substrate from 0,5 to 5 cm/s, scanning speed from 1 to 10 kHz. The crystallographic structure was studied by X ray Diffraction (XRD). Scanning Electron Microscopy (SEM) was carried out to explore the surface structures and the chemical composition was determined via energy dispersive X ray spectroscopy (EDX). The mechanical were studied by nanoindentation tests.
The obtained results demonstrate a formation of (Ti,Nb)Al3 fractions randomly distributed in biphasic structure of intermetallic (Ti,Nb)Al3 particles, dispersed in ±-Al solid solution . The evaluated (Ti,Nb)Al3 lattice parameters are independent of the speed of the specimen motion and therefore the alloying speed does not affect the lattice parameters and thus, does not form additional residual stresses, strains etc. It was found that lower velocity of the specimen motion during the alloying process develops more homogeneous structures. The metallographic analyses demonstrate a formation of surface alloys with very high hardness. Our results demonstrate maximal values of 780 HV [kg/cm2] and average hardness of 650 HV [kg/cm2].
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