Laser gas assisted melting of preprepared alumina surface including TiC particles at surface

Abstract

Laser gas assisted remelting of prepared alumina surface is carried out. In the prepreparation cycle, carbon film containing TiC particles of 50 μm thickness is formed at the alumina surface. Laser controlled melting is carried out on the preprepared alumina surface at high pressure nitrogen environment. The microstructural and morphological changes in the laser treated section are examined using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction (XRD). The microhardness of the resulting surface is measured, and the residual stress developed in the surface is determined from the XRD technique. ABAQUS code is used to predict the temperature and stress fields in the laser treated region. It is found that a dense structure containing undissolved TiC particles is formed in the surface region of the laser treated layer. The nitride compounds of AlN and Al(C, N) are formed at the surface during the laser treatment process. The columnar structure is formed beneath the dense structure. The predictions of residual stress agree with the results obtained from the XRD technique.