The design of materials with desired properties is a challenge for most industries. It has become even more critical with the innovations in additive manufacturing (AM) and 3D printing technologies allowing for higher resolution of the metal parts’ topology. The impact between particles and the material surface is a micro-scaled physical phenomenon found in various technological processes and while studying the mechanical properties of materials. High-velocity interaction between particles and non-flat surfaces is relevant to processes occurring in AM, such as cold spray CS. The dissertation aimed to study strain-rate-dependent plasticity at a wide range of strain rates. Particular cases of the axisymmetric particle-substrate contact were simulated using an elastic material model and different plasticity models (PM). The problem is approached by numerical simulation applying finite element analysis (FEA) using strain, strain-rate, and temperature-dependent plasticity models. The investigated problem was high-rate elastic-plastic deformation of the micro-sized copper particle impacting against a copper substrate. The thermomechanical FEA was performed using selected PM. The perfor-mance of the strain-rate-dependent Johnson–Cook (J–C), Cowper–Symonds (C–S) and strain-rate-independent Ludwig models was studied by comparing displacements, velocities, strains, strain rates, stresses, contact forces, temperatures, and their contribution to material yield stress. The study has shown the importance of the high-strain-rate PM and its adequacy to experimental data. Both rate-dependent models complement each other and may be regarded as soft and hard bounds of the solution. The new two-function combined model containing two independent functions for each of the two regimes was suggested. The proposed model describes a low strain-rate sensitivity regime using the modified J–C expres-sion while allowing to fit the model for experimental results in a high strain-rate sensitivity regime using the modified C–S expression. This combination can describe both low- and high-strain-rate regimes giving the minimum deviation from experimental results. The performance of the new plasticity model was investigated in elastoplastic particle impact and dynamic indentation simulations. The new model shows an equal contribution of strain and strain rate hardening during impact. Additionally, the dissertation addresses normal contact interaction between particles and spherical surfaces. Here, the focus is on showing the contribution of colliding particle radii to interaction parameters. The results include contact duration, contact surface area, displacement, heat energy, stress, and strain rate.