Nanocomposites and nanomaterials

Structure and phase transformations of amorphous-nanocrystalline Al-based alloys 
Nykyruy Yu.S.1 Mudry S.I.1, Kulyk Yu.O.1, Shtablavyi I.I.1, Serkiz R.Ya.2
1 Metal Physics Department, Ivan Franko National University of Lviv, Kyrylo and Mephodiy str. 8, Lviv 79005, Ukraine. 
E-mail: yuliya.nykyruy@lnu.edu.ua
2 Solid State Physics Department, Ivan Franko National University of Lviv, Kyrylo and Mephodiy str. 8, Lviv 79005, Ukraine.

Al–Si–Ni amorphous and nanocrystalline alloys are now interesting due to their unique combination of high strength, high elasticity, good wear and corrosion resistance. Physical properties of a material depend on structure and phase composition. Thus, the investigation of the Al-based amorphous alloys structure after different kinds of treatment is interesting both from fundamental and practical application viewpoints.
The Al65Si25Ni10 and Al70Si20Ni10 alloys were manufactured in the form of ribbon by rapid cooling from the melt using the melt-spinning technique. The as-quenched ribbon structure was mostly amorphous with a small content of nanocrystalline phase. The as-obtained ribbons were investigated by DTA-method using synchronous thermal analyzer Linseis STA PT 1600. Heating was performed at rate of 6 K/min from 293 K up to 673 K. Structure transformations of Al65Ni10Si25 amorphous-nanocrystalline ribbon were investigated under three different conditions of heating. 1 – The ribbon was heated in the camera of a high-temperature diffractometer in the atmosphere of high purity helium and X-ray diffraction curves were taken at the temperatures 343 K, 463 K, 533 K and 608 K. 2 – The ribbon samples were annealed in a chamber in vacuum atmosphere (1.33 Pa) during 1 hour at temperatures 463 K, 533 K and 608 K. 3 – The ribbon was heated using laser irradiation with the wavelength of 1.06 µm, power of 50 W and exposure times of 0.5, 0.6, 0.7 and 0.8 s. After annealing and laser irradiation the ribbon samples were studied using X-ray diffraction method (Со-Kα radiation, λ = 1.7902 Å). Structural changes of irradiated surface were performed using scanning electron microscopy (SEM).