Multi-cycle electron-ion-plasma alloying of silumin: structure, properties

The aim of the work is to analyze the results and identify the regularities of the silumin surface layer modifying using multi-cycle combined processing methods. Such processing combines the formation of the «film (metal)/(silumin) substrate» system with subsequent surface irradiation with an intense pulsed electron beam of submillisecond duration in single cycle. The silumin processing was carried out on «COMPLEX» setup. This setup was designed and created in the HCEI SB RAS. Titanium was chosen as the alloying element. The thickness of the deposited titanium film in each processing cycle is 0.5 microns. The number of cycles of alloying 1; 5 and 10. The process of surface alloying consisted in the sequential implementation of ion cleaning and heating in an argon plasma of a non-self-sustained arc discharge with thermionic and hollow cathodes with a negative biasing of the sample (initial samples heating to a predetermined temperature, cleaning and activation of the treated surface); plasma-assisted (using argon plasma) arc deposition of metal film; electron-beam processing of the «film (titanium)/(silumin) substrate» system using a low-energy microsecond pulsed electron beam. It was established that multi-cycle alloying of silumin AK12 with titanium leads to silicon and intermetallic inclusions dissolution in the surface layer up to 30 microns thick and to submicro-nanocrystalline multiphase structure formation. The structure obtained is characterized by high values of microhardness and wear resistance. These values exceed the corresponding characteristics of cast silumin by 1.4 and 14.2 times, respectively.

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