Thermal Stability of the Structural and Phase State of Aluminum and Alloys of the Al–Si System Doped with Zirconium Atoms under the Influence of Compression Plasma Flows

The structural and phase state of the surface layers of Al, Al-Si, and Al-Si-Cu-Mg alloys doped with zirconium atoms under the influence of compression plasma flows is studied. It is established that metastable compounds Al₃Zr with the crystal structure L1₂ and (Al, Si)₃Zr with the structure D0₂₂ are formed in the doped layers of aluminum and silumins, respectively. It is shown that doping of the studied alloys with zirconium makes it possible to increase the microhardness of the surface layer by 1.4–3 times. A study of the thermal stability of the structural and phase state of the doped layers at 550°C showed that, as a result of aluminum annealing, the Al₃Zr phase with the L1₂ structure transforms into the Al₃Zr compound with the D0₂₃ structure, and in the alloys of the Al–Si system, the decomposition of (Al,Si)₃Zr and the formation of ZrSi₂ occur. It is noted that the synthesized surface layer has increased temperature strength.