Study on the detailed micro-structural characteristics of Laser Cladding in terms of porosity distribution, dilution of alloying elements and stresses in the laser melted zone using focused ion beam tomography

点击翻译按钮获取中文摘要

Surface modifications by laser are being practiced now for the last 1-2 decades. There have been several publications, where different surface property modifications have been studied. This includes mainly, corrosion, oxidation, wear, friction and hardness. Useful information obtained from these siudies has also helped in adaption of this technique by various industries, as an alternative process. For example, laser hardening has been adopted by many industries in place of conventional case-carburizing, ion-nitriding and plasma nitriding. Laser alloying and cladding have been extended to the repair of several complicated and expensive components such as ship parts, crank shafts and aero-engine turbine blades. We have been carrying oul work on laser surface alloying and cladding and contributed towards the modification of surfaces, such as steel, stainless steels, titanium in terms of their corrosion, oxidation and wear behavior. Detailed studies confirm the surface modification as per the mechanism of oxidation and corrosion. We have also used this technique to fabricate near-net shaped components using laser forming.It is however, felt that the micro-mechanisms within the laser melted zone or cladding are still not clear. Whether it is the role of densification due to laser treatment or it is the change in microstructure (amorphous or micro-crystalline) and also the role of dilution of the alloying elements is not very clear. During our recent interactions and my short stay at the chair of functional materials (Prof. Dr. F. Mücklich) at Saarland University, I found a dedicated interest towards this kind of study. The instituie has basic laser facilities and is very strong in micro-structural evaluations using sophisticated techniques such as focused ion beam tomography and XRD and other surface analytical tools. It was therefore proposed to work together on this field - with our strong expertise in laser alloying and cladding and their strong expertise in micro-structural evaluations.