Advanced laser processing of metals

Summary form only given. The application of lasers span the entire commercial and industrial scene starting from the CD player at home to welding in automobile and aircraft plants. Processes such as welding and cutting of components in order of meters, drilling dimensions of mm to /spl mu/ms are widely accepted in manufacturing. Future applications in manufacturing include: nanometer size powder generation by laser ablation; Angstrom to micron size deposition by laser CVD; mm scale coating by laser cladding; surface modification and meter scale components by direct metal deposition. The laser is a tool which can provide energy density varying from 10/sup -3/ watts/cm/sup 2/ to 10/sup 12/ watts/cm/sup 2/. They have a wavelength range varying from UV (/sup a_/193 nm) to far infrared (10.6 /spl mu/m). Recently, high brightness lasers have created new opportunities for laser processing applications. This inertialess tool of optical energy has the potential to start a new era. The preferred approach for successful process development is to apply "atomic level understanding to applications". This paper discusses the science base for many of the important laser processing techniques. Emission, absorption and laser induced fluorescence spectroscopy have been applied for studying interaction physics whereas transport models are used for quantitative understanding of the effects of process parameters on the materials. Electron optical techniques are applied to characterize the processed materials and whenever possible an effort has been made to establish structure-property-process-parameters relationship.