I. Smurov

Optical Monitoring in Laser Cladding of Ti6Al4V

The TRUMPF 505 DMD machine with a 5-kW CO2 laser was used to enable scaling-up laser cladding (LC) to an industrial level. The aim of this study is to enhance product quality and to assure process stability and reproducibility by means of optical monitoring. Two originally developed pyrometers and an infrared camera FLIR Phoenix RDAS™ are employed in the LC of Ti6Al4V powder. The variations of brightness temperature versus laser power and cladding velocity are analyzed. A CCD camera-based diagnostic tool is applied for online monitoring of particle-in-flight velocity in coaxial powder injection.

Determination of True Temperature in Selective Laser Melting of Metal Powder Using Infrared Camera

The objective of this study is to restore the true temperature in during the process of Selective Laser Melting (SLM) of metal powder (in the present case INOX 316L), that is the actual problem in laser assisted additive technologies. To meet this objective, at the first stage, the temperature was measured on the surface of metal substrate INOX 304L without a powder layer. Based on the results of studies the method of temperature measurementof the molten pool surface on metallic plates and during melting of metal powder layer, that were exposed to laser radiation, using an infrared camera (IR), in the present case FLIR Phoenix RDAS TM, was proposed. To restore the true temperature based on the brightness temperature values measured by IR camera, the results of temperature measurements were compared with the width of the molten track on the surface of the plate in the absence of powder. In case of SLM, the results of IR camera measurements were compared with the width of a welded track (bead). The true temperature profiles and temperature gradients values were determined along the axis of the laser beam for melting of plates without powder. In the case of powder melting, the developed method allows to determine the influence of several key SLM parameters on the molten pool shape.

Application of laser surface engineering to solve tribological problems

The methods of laser surface engineering, including laser cladding, laser alloying from predeposited layers, and laser alloying from the gas phase have been applied to increase the wear resistance and decrease the coefficient of friction of metallic surfaces. Laser cladding has been applied to deposit metal matrix composites that consist of CuSn, stellite, stainless steel, and bronze, which act as solid lubricant reinforced with nanostructured WC ceramics with Co binding. Laser alloying of bearing steel with Sn increases the lifetime of oil turbo drills. Wear tests of Ti alloys doped with nitrogen from a gas atmosphere have demonstrated a viable possibility to apply the developed method to fabricate frictional couples.