Multiphysics Theoretical Evaluation of Thermal Stresses in Laser Machined Structural Alumina

Abstract

Lasers are being explored as innovative machining tools to efficiently fabricate complex shapes and contours in hard and brittle structural ceramics. Although, the concentrated nature of laser beam is capable of providing suitable conditions for efficient machining of structural ceramics, it often generates steep temperature gradient that leads to generation of the detrimental thermal stresses. These thermal stresses are likely to be sufficient to nucleate the micro-cracks and subsequent crack propagation or growth can lead to failure. In light of this, a theoretical approach was employed in the present efforts to evaluate the thermal stresses during laser machining of structural alumina ceramic. A multistep multiphysics computational model was designed and developed to estimate thermal stresses during multidimensional laser machining of structural alumina. The environmental scanning electron microscopy (ESEM) observations were carried out to detect the micro-cracks generated due to the thermal stresses on the surface of laser machined alumina under various machining conditions.