Advances in Laser Nitriding Methods and Apparatus for Metals and Alloys

Abstract

Laser gas nitriding is a promising method used to improve the surface properties of components. Accordingly, the latest developments in this method are reviewed. It is found that currently three laser gas nitriding methods have been developed. They are namely, the diffusion laser gas nitriding (DLGN), the conventional laser gas nitriding (CLGN), and the duplex treatment laser gas nitriding (DTLGN) processes. The basic principles of these methods were reviewed and discussed. Recent developments on laser gas nitriding of titanium Ti–6Al–4V alloy are reviewed as a case study to demonstrate the advances on the laser gas nitriding aspects. The processing parameters have important effects on the resulting characteristics of titanium and titanium alloys. Several researchers recommend carrying out process parametric studies and optimization. Therefore, this subject is reviewed and discussed. The resulting microstructure and mechanical properties of laser gas nitrided Ti–6Al–4V alloy specimens are presented and discussed. The problems to be resolved and the prospects in the field of laser gas nitriding of titanium and titanium alloys are discussed. Finally, results obtained from each of the previous three methods were presented and discussed to complete the picture of the laser gas nitriding.