الفهرس 
Cover EnglishOnly 14 pages are availabe for public view
 |  | from | 152 |  |  |
| | | from | 152 | | |
Abstract
Aluminum alloys are important structural materials because of their high strength to weight ratio. Unfortunately, due to their high reflectivity and complexity in heat treatment, aluminum alloys are some of the hardest metals to be laser treated successfully and very high laser power is usually required. In the present work detailed study of the interaction of laser light with a special aluminum alloy (containing zeolite) compared with pure aluminum is presented. The inclusion of zeolite material inside the aluminum alloy gives the alloy expandable volume under compression. Three lasers have been used throughout the present study. An Nd:YAG laser (1064 nm), with pulse width in nanosecond scale, which has the maximum absorption coefficient with aluminum alloy, and two femtosecond lasers; Ti:sapphire laser source (800 nm), and Satsuma laser source (1030 nm). This makes it possible to study the effect of both the laser wavelength and the pulse duration on the interaction mechanisms as well as the LIBS analysis. The factors which affect the vulnerability of targets to a laser beam have been studied. These are divided into target material related factors and laser source parameters beside the effect of ambient conditions. The study has been focused on the effect of the ambient conditions (gas nature and pressure, as well as the temperature) on melt mobilization, and target surface morphology. The laser ablation process of the aluminum alloy was simulated and compared with the experimental results successfully. The effect of ambient conditions on LIBS analysis was also studied beside the effect of laser pulse duration (nanosecond or femtosecond). Laser ablation mechanisms as well as the ablation rate of aluminum alloy targets of different hardness were well studied. These experimental results were compared with the theoretical outputs of a computer model which simulate the process of laser-target interaction with usage of a (Mat-Lab) package. The surface hardness of the samples under investigation is determined by measuring the spectral intensity ratios of the ionic to atomic spectral lines in the LIBS spectra of samples having different surface hardness values that have been conventionally measured before for comparison.