화학공학소재연구정보센터
Applied Surface Science, Vol.389, 768-774, 2016
Formation and characterization of Al-Ti-Nb alloys by electron -beam surface alloying
The combination of attractive mechanical properties, light weight and resistance to corrosion makes Ti-Al based alloys applicable in many industrial branches, like aircraft and automotive industries etc. It is known that the incorporation of Nb improves the high temperature performance and mechanical properties. In the present study on Al substrate Ti and Nb layers were deposited by DC (Direct Current) magnetron sputtering, followed by electron-beam alloying with scanning electron beam. It was chosen two speeds of the specimen motion during the alloying process: V-1= 0.5 cm/s and V-2 =1 cm/s. The alloying process was realized in circular sweep mode in order to maintain the melt pool further. The obtained results demonstrate a formation of (Ti,Nb)Al-3 fractions randomly distributed in biphasic structure of intermetallic (Ti,Nb)Al-3 particles, dispersed in ci-Al solid solution. The evaluated (Ti,Nb)Al-3 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 775 HV [kg/cm(2)] and average hardness of 673 HV [kg/cm(2)]. (C) 2016 Elsevier B.V. All rights reserved.