The Morphology and Mechanical Properties of ESD Coatings before and after Laser Beam Machining

Abstract

Electro-spark deposition (ESD) and laser beam machining (LBM) are the technologies using the concentrated energy flux. This paper deals with the issue of the impact of laser modification on the morphology and mechanical properties of carbide/copper coatings produced by electro-spark treatment. The coatings were applied to C45 carbon steel samples using the EIL-8A device. The following three types of electrodes made using the powder metallurgy (PM) hot pressing technique, from copper and tungsten carbide powders of different percentage compositions, were used for the coatings: 25% WC and 75% Cu; 50% WC and 50% Cu; and 75% WC and 25% Cu. Laser modification of the surface layers was performed with an Nd:YAG laser. The research focused on the analysis of the morphology of coatings applied by electro-spark technology before and after laser processing. The analysis of the morphology of electro-spark coatings revealed that the coatings had microcracks and pores. The laser beam machining of ESD coatings led to the homogenization of chemical composition, fragmentation of the structure, and elimination of microcracks. In addition, measurements of porosity, microhardness, adhesion, and analysis of XRD phase composition of the electro-spark coatings were performed. Laser processing proved to have a positive effect on improving the adhesion of coatings and reducing their porosity. This paper also presents a simulation model of heat transfer processes for the case of laser radiation impact on a WC-Cu coating. The developed numerical model, describing the influence of laser treatment on the distribution of temperature fields in the heated material (at a given depth) is of significant importance in the development of treatment technologies. Laser-modified ESD coatings perform anti-wear and protective functions, which enable their potential application in means of transport such as rolling stock.

Numerical analysis of laser-welded flange pipe joints in lap and fillet configurations

“…Stress values in HAZ are elevated with respect to BM, and the values calculated in the base material are relatively low. Due to high energy density in the LBW, heat accumulation compare to conventional welding methods is low, therefore stress-strain value are lower (Radek, 2020). The stress states in the welded joint need to be controlled; however, the obtained results shows that no additional heat treatment is required.…”

State-Of-The-Art and Trends in CO2 Laser Cutting of Polymeric Materials—A Review

“…Goeke and Emmelmann [ 44 ] performed experiments for the investigation of the influence of materials properties on the cut quality. Radek et al [ 66 ] performed the experimental investigation in laser cutting assisted modification by electrode spark deposition to analyze the surface microhardness, porosity, and adhesion. It was found that the aforementioned mechanical properties of the modified copper-tungsten electrodes are significantly influenced by the machined surface morphology.…”

Spark Plasma Sintering of WC-Based 10wt%Co Hard Alloy: A Study of Sintering Kinetics and Solid-Phase Processes

“…Furthermore, much attention is paid to studying the effect of thermal cycling modes on hard alloys’ mechanical and tribological properties. The processes of WC material fabrication by electro spark deposition (ESD) and laser beam machining (LBM) methods and also Cr-WC electrodeposition by direct (DC) and pulsed (PC) currents are topical [ 15 , 16 ]. WC production simplification and cheapening tasks deserve particular attention [ 17 ].…”