Laser-assisted microscale deformation of stainless steels and ceramics

We investigate deformation of stainless steel and ceramic specimens with a precision of the order of tens of nanometers using a pulsed laser beam. Such a technique is useful, for example, in a process of removing distortions on magnetic head components to achieve a better contact between the magnetic disk head and the hard disk surface. Experiments are conducted to study the bending behavior of stainless steel and ceramics due to laser irradiation. A pulsed Nd:YLF laser beam is used to scan over the specimen to create out-of-plane deformation. The amount of deformation from each laser scan is correlated with laser and processing parameters. A theoretical model of the laser deformation process is presented based on thermo-elasticity-plasticity. The laser deformation process is explained as the result of the laser-induced nonuniform distribution of the compressive residual strain. Numerical simulations are carried out to estimate the laser-induced temperature field, the residual stress field, and the amount of deformation of the specimen. These theoretical studies help us to understand the complex phenomena involved in the pulsed-laser deformation process.