Selective electron beam surface alloying of aluminum with TiCN nanoparticles

Highlights: • A method based on analytical solution of the heat transfer equation is proposed. • The comparison of the experimental with the theoretical results show good agreement. • The hardness increases after electron beam modification with TiCN nanoparticles. -- Abstract: In this work we present a mathematical model of the temperature distribution in layers formed by selective electron beam surface alloying of Al with TiCN nanoparticles following circular trajectories. The model is based on analytical solution of the heat transfer equation using Green's functions. The obtained numerical results show that the frequency and radius of the electron beam rotation have the strongest influence on the distribution of the temperature field. The molten zone depth decreases from 25 to 17 µm for frequency variation from 5 to 10 kHz. Decreasing the beam rotating radius from 2.6 to below 2 mm leads to an increase in the molt depth from 10 to more than 30 µm. The model is verified by experimental investigation of layers formed by selective electron beam alloying of Al with TiCN nanoparticles, where the phase composition, layer thickness and microhardness were determined. The results show the successful incorporation of the nanoparticles in the surface layer, leading to an increase in their microhardness by 16–22 times. A good agreement is obtained between the experimental and the numerical results regarding the thickness of the molten zone, confirming the feasibility of the proposed model.