Effect of surface activation and internal mechanical stress on the diffusion of oxygen atoms in TiNi alloys in electron beam treatment

The paper studies the nonlinear effect of nonequilibrium surface activation and internal mechanical stress on the diffusion of oxygen atoms from an adsorbed surface layer of TiNi alloys deep into the materials in electron beam treatment. The mathematical model proposed in the paper includes heat, diffusion and kinetic equations with initial and boundary conditions appropriate to pulsed electron beam treatment. The kinetic parameters are estimated, and the spatial and temporal distributions of temperature, concentration and stress are calculated for a wide range of parameters. The heat penetration and diffusion depths are determined; the results obtained with and without regard for activation are compared.