Laser treatment of boron carbide surfaces: Metallurgical and morphological examinations

•Dense layer with fine grains is formed at surface.•Irregular shaped grains and dendrites are formed below dense layer.•Assisting gas forms nitride species (BN and BC2N) at surface.•Fracture toughness of treated surface reduces because of high hardness.•Residual stress is compressive and the maximum...

Full description

Saved in:
Bibliographic Details
Published in:Journal of alloys and compounds 2014-08, Vol.603, p.125-131
Main Authors: Yilbas, B.S., Karatas, C.
Format: Article
Language:English
Subjects:
B4C tile
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Diffraction
Exact sciences and technology
Fracture toughness
Laser treatment
Lasers
Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties
Materials science
Metallurgy
Microhardness
Physics
Residual stress
Scanning electron microscopy
Surface treatments
Surfaces and interfaces
thin films and whiskers (structure and nonelectronic properties)
X-rays
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Dense layer with fine grains is formed at surface.•Irregular shaped grains and dendrites are formed below dense layer.•Assisting gas forms nitride species (BN and BC2N) at surface.•Fracture toughness of treated surface reduces because of high hardness.•Residual stress is compressive and the maximum residual stress is about 0.9GPa. Laser treatment of B4C tile surfaces is carried out under high pressure nitrogen assisting gas environment. Morphological and metallurgical changes in the laser treated layer are examined by incorporating scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction. Microhardness and fracture toughness of the laser treated surface are determined from the indentation data. Residual stress formed at the treated surface is obtained by using X-ray diffraction technique. It is found that laser treated surface is free from large scale asperities including cracks and voids; however, some locally scattered shallow cavities with 1.5–2μm widths are formed at the surface because of high temperature processing. Dense layer, consisting of fine grains, and formation of nitride species (BN and BC2N) enhance microhardness and lower fracture toughness at the surface. Residual stress formed in the treated layer is compressive and the maximum residual stress is in the order of −0.9GPa.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2014.01.219