Temperature-dependent determination of electron heat capacity and electron-phonon coupling factor forFe0.72Cr0.18Ni0.1

Abstract

A theoretical approach using ab initio calculations has been applied to study the interaction of an ultra-short laser pulse with the metal alloy Fe0.72Cr0.18Ni0.1 (AISI 304). The electronic structure is simulated by taking into account the chemical and magnetic disorder of the alloy by the coherent potential approximation implemented in a fully relativistic Korringa-Kohn-Rostoker-formalism in the framework of spin density functional theory. Utilizing these predictions we determined the electron heat capacity and the electron-phonon coupling factor of Fe0.72Cr0.18Ni0.1 in dependence on the electron temperature for two-temperature model applications. Compared with pure Fe a maximum deviation of 5 % for the electron heat capacity and 25 % for the electron-phonon coupling factor is found.

Tailored Sub-micrometer Periodic Surface Structures via Ultrashort Pulsed Direct Laser Interference Patterning

“…The employment of the thermophysical properties based on the fitting of data for Fe does not differ significantly for 100Cr6. Indeed, recent results indicate that the temperature dependent electron heat capacity of a steel alloy is not substantially different from that predicted for Fe [62]. Similarly, our calculations indicate that a more rigorous computation of the electron-phonon coupling is not anticipated to produce substantially different morphological results [22].…”

Regular Nanowire Formation on Fe-Based Metal Glass by Manipulation of Surface Waves

“…Except for the increasing number of nanowire growth, all the structure features, including the modulation height of 21.4 nm and structure period of 185 nm, are nearly consistent with the sole nanowire structure. It should be noticed that our observation of the highly regular HSF structures oriented parallel to the laser polarization cannot be well understood by the hydrodynamic theory because the material of Fe-based metallic glass tends to have a large electron-phonon coupling constant of 1.7 × 10 18 W/m 3 /K [34]. In order to verify the spatial restriction of the groove width for the formation of the sole long nanowire structure, we employed a wide scratched groove with the opening width of 3.6 µm to repeat the above experiment; the corresponding results are shown in Figure 6.…”

“…Except for the increasing number of nanowire growth, all the structure features, including the modulation height of 21.4 nm and structure period of 185 nm, are nearly consistent with the sole nanowire structure. It should be noticed that our observation of the highly regular HSF structures oriented parallel to the laser polarization cannot be well understood by the hydrodynamic theory because the material of Fe-based metallic glass tends to have a large electron-phonon coupling constant of 1.7 × 10 18 W/m 3 /K [ 34 ].…”

Prediction of Thermal Damage upon Ultrafast Laser Ablation of Metals

“…For the regime prevailing at low fluences, the ablation depth is determined by the optical penetration depth of the material. On the other hand, at high fluences, the energy transport is dominated by the electronic heat diffusion during the laser pulse, which is too low for low fluences, but increases at higher electron temperatures reached at high laser fluences [32][33][34][35]. This is why we applied the two different heat damage thresholds, or colors: to better interpret the calculated heat values listed in Figure 3c.…”