Nanosecond laser ablation of thin film material libraries

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Rebegea, Simina Aurelia (2018). Nanosecond laser ablation of thin film material libraries. University of Birmingham. Ph.D.

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Abstract

This work offers a novel approach to the investigation of material response in nanosecond laser ablation, by irradiating a thin film material library (having small variations in the chemical composition) with a beam of constant parameters. The method could be used as a way to assess the machining capability of a wide range of materials. Single-pulse craters were obtained with nanosecond infrared lasers (Nd:YAG, 1064 nm, 30-55 ns). The influence of reflectivity, thermal properties, surface and sub-surface morphology of the target material are correlated with the variations in crater geometry, morphology and the amount of removed material. Pure Cu, Al and Ni films and their binaries were studied to establish typical craters and to illustrate how a change in the parent material affects the workpiece after irradiation respectively. The study of the ternary compositional gradients irradiated with constant laser parameters extends upon these findings, and represents, to this point, the first work of its type. A second film (Cu-Al-Zr) was analysed to confirm that the variations in crater geometry and morphology were not material-specific. It is also shown that nanosecond laser ablation of thin films (with minimal thermal damage to the substrate) can be achieved with a typical Gaussian beam.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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