Water assisted laser heat treatment of polycrystalline cubic boron nitride tool materials

Abstract

<p>This thesis explores a new development in improving the surface properties to ultrahard material using a variety of laser systems, which are CO2 continuous wave laser water-jet system and Nd:YAG pulsed laser system. Two different types of cBN materials were used, which were bindered 82%cBN/18%AlN and 55%cBN/45%TiN. In the heat treatment using the CO2 continuous wave laser water-jet system, the effects of different types of gases, number of laser beam passes, and distribution of laser power were studied. In addition, in the heat treatment using the Nd:YAG pulsed laser system, the effects of quenching and number of laser beam passes were studied as well. In both studies, the hardness was investigated using Knoop hardness measurement, and the microstructures of the sample surfaces were characterized using Scanning Electron Microscope (SEM).</p>