2011 2nd International Conference on Chemistry and Chemical Engineering IPCBEE vol.14 (2011) © (2011) IACSIT Press, Singapore
Nanocrystalline TixAl1-x prepared by Bulk Alloying and Thin Films Methods Jinan B. AL-Dabbagh1, Ibrahim. Odeh2 1
Faculty Of Industrial Science and Technology, University Malaysia Pahang, Kuantan ,Malaysia. 2 Department of Physics, College of Science, Yarmuk University, Irbid-Jordan
Abstract. In the present work, TixAl1-x alloys with different composition ratios (x=0.25, 0.5, 0.75) have been prepared. These alloys were fabricated by gradually solidification of melt of (Ti- Al) metals under vacuum at 1000-12800 0C .These alloys was then thermally evaporated to form thin films of thickness 200 nm onto glass substrates obtained under vacuum of 10-6 Torr. The crystallalinity and the microstructure has been analyzed for both the bulk and thin films using X-ray diffraction study indicating polycrystalline structure (hcp)type γ(TiAl) and α-(Ti3Al), (TiAl3) phases for both bulk and thin films. The crystallite size has been calculated using Sherrer equation which decrease in size from 14nm-to-9nm for thin films, and from 27.6nm- to-9.3nm for bulk samples as the weight percentage of Ti increases. On further annealing of these thin films alloys increases the crystallite size due to recrystallization process. Keywords: TiAl alloys, nanostructure materials, thin films
1. Introduction Titanium aluminide (TiAl) base alloys are being developed as promising class of high temperature structural materials for their low density, high stiffness, excellent strength at elevated temperatures and good oxidation resistance[1]. Some applications explored include turbine engine blades and structural component for air craft and exhaust engine valves for automobiles. Microstructure control analysis was used on developing the creep resistance of TiAl alloys with ultrafine grain. Thin film TiAl alloys were consider as structural materials in a verity of aerospace applications[2]. Ternary additions of (Nb,V,Ta) are frequently used to make these materials more ductile at room temperature. TiAl, alloys occupies an important position in structural intermetalices with combine many good properties offered by metallic and ceramic materials. The aim of this work is to investigate the effect of composition ratios on structural and microstructure properties of TixAl1-x alloys in both bulk and thin films forms.
2. Experimental TixAl1-x alloys were prepared by mixing Al and Ti metals of high purity (99.995) with different ratio (0.25, 0.5, 0.75) as given in Table 1 The weighted Al and Ti metals were loaded into a clean and baked quartz ampoule, then evacuated to ~10-3 Torr. The ampoule was then sealed and placed inside electric furnace, the temperature was raised gradually to 1000-1280oC depending on the x-ratio and kept at this temperature for 8hr. then cooled gradually to room temperature at a rate 5C0/min . Fig.1 show the phase diagram for TiAl system [3]. The alloys was then taken out for X-ray diffractions and for thin films preparation.
Jinan Basheer AL-Dabbagh Tel; +6095492783, Fax;+6095492766, E-mail:
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TixAl1-x alloys thin films have been prepared by thermal evaporation technique under vacuum
