Thermal History Mapping in Powder Bed Laser Sintering at the Micrometer Scale.

Area of Science:

• Materials Science
• Optics
• Laser Physics

Background:

• The optical properties of 0.5% Mn-doped ZnAl2.2O4 depend on Mn2+ ion site occupancy (octahedral/tetrahedral), influenced by thermal history.
• Understanding laser-material interactions is crucial for applications relying on controlled thermal processing.

Purpose of the Study:

• To investigate the influence of laser defocusing on thermal gradients in Mn-doped ZnAl2.2O4 thin films.
• To correlate laser defocusing with material thermal history and luminescence properties at the micrometer scale.

Main Methods:

• Fabrication of 0.5% Mn-doped ZnAl2.2O4 thin films using screen printing.
• Laser irradiation of films with varying defocusing heights (z) to create single laser tracks.
• Analysis of luminescence properties around laser tracks to determine thermal history.
• Semiquantification of spatial thermal gradients using a thermal sensor and thermal modeling.

Main Results:

• Spatial thermal gradients, perpendicular to laser tracks, were semiquantified for different defocusing conditions.
• Laser defocusing was shown to decrease the magnitude of these thermal gradients.
• Luminescence mapping provided micrometer-scale insights into the thermal history of the material.

Conclusions:

• Laser defocusing is an effective parameter for controlling thermal gradients during laser processing of Mn-doped ZnAl2.2O4.
• The study demonstrates a method for semiquantifying thermal gradients and determining material thermal history via luminescence.
• Findings contribute to understanding laser-induced modifications in doped spinel materials.