STUDY OF TEMPERATURE FIELDS AND THERMAL STRESSES IN H13A TOOL MATERIAL UNDER FEMTOSECOND LASER PROCESSING

Abstract

The study presents a theoretical modeling of the nanostructure formation process in H13A tool material under the influence of femtosecond laser radiation, taking into account the following technological parameters: heat flux density
(q = 10⁸–10¹¹ W/m²) and pulse duration (10⁻¹⁶–10⁻¹⁰ s). The research was based on a comparison of two approaches to defining the thermophysical and thermomechanical properties of materials: a quantum-mechanical method that considers the discrete atomic structure, and a stochastic method oriented toward probabilistic distributions.

Modeling of temperature fields, their rates of change, and thermal stresses at different depths was performed using numerical methods adapted to extreme heating and cooling regimes. The results showed that within the quantum-mechanical approach, the temperature values and temperature rise rates (V) are significantly higher than those predicted by the stochastic approach, especially at high heat flux densities (above 10¹⁰ W/m²) and short pulse durations (10⁻¹⁶–10⁻¹⁴ s). The distribution of thermal stresses exhibited pronounced heterogeneity: maxima were observed at q ≈ 10⁹ W/m² (due to peak temperature gradients), while minima occurred at q ≈ 10¹⁰ W/m², which promotes phase transformations and nanostructure self-organization. It was shown that at pulse durations of 10⁻¹⁰–10⁻¹² s, thermal stresses can independently initiate nanostructurization, whereas in other cases they accelerate the process. The quantum-mechanical method demonstrates advantages in accurately predicting extreme regimes, providing higher stress and temperature peaks that are critical for amorphization and the formation of ultrafine phases. At the same time, the stochastic approach yields more conservative estimates suitable for preliminary screening. The analysis emphasizes that temperature data alone are insufficient for model validation; the key factor is the comparison of nanostructure (cluster) volumes obtained experimentally and theoretically using atomic force microscopy, X-ray diffraction, and spectroscopy techniques. Integration of both approaches into a hybrid model will enable optimization of laser processing parameters for the development of materials with enhanced wear resistance, corrosion resistance, and biocompatibility. The results open prospects for industrial applications in the aerospace, automotive, medical, and other industries. Further work will focus on experimental verification and technology scaling.