Laser cladding of Inconel 625-based composite coatings reinforced by porous chromium carbide particles

基于Inconel 625的激光熔覆多孔性碳化铬增强复合材料涂层

Optics & Laser Technology, Volume 94, 1 September 2017, Pages 6-14

Damian Janicki

Abstract：Inconel 625/Cr3C2 composite coatings were produced via a laser cladding process using Cr3C2 reinforcing particles presenting an open porosity of about 60%. A laser cladding system used consisted of a direct diode laser with a rectangular beam spot and the top-hat beam profile, and an off-axis powder injection nozzle. The microstructural characteristics of the coatings was investigated with the use of scanning electron microscopy and X-ray diffraction. A complete infiltration of the porous structure of Cr3C2 reinforcing particles and low degree of their dissolution have been achieved in a very narrow range of processing parameters. Crack-free composite coatings having a uniform distribution of the Cr3C2 particles and their fraction up to 36 vol% were produced. Comparative erosion tests between the Inconel 625/Cr3C2 composite coatings and the metallic Inconel 625 coatings were performed following the ASTM G 76 standard test method. It was found that the composite coatings have a significantly higher erosion resistance to that of metallic coatings for both 30° and 90° impingement angles. Additionally, the erosion performances of composite coatings were similar for both the normal and oblique impact conditions. The erosive wear behaviour of composite coatings is discussed and related to the unique microstructure of these coatings.

Wear resistance in the soil of Stellite-6/WC coatings produced using laser cladding method

激光熔覆法制备Stellite-6/WC合金镀层在土壤中的耐磨性

International Journal of Refractory Metals and Hard Materials, Volume 64, April 2017, Pages 20-26

Dariusz Bartkowski, Aneta Bartkowska

Abstract：The paper presents the study results of macro- and microstructure, microhardness, phase composition and practical application of Stellite-6/WC metal matrix composite (MMC) coatings produced using laser cladding technology. For the preparation of MMC coatings the Yb:YAG disc laser with a rated power equal 1 kW was used. The laser beam was controlled using a 5-axis CNC machine. The powder mixture was fed to laser beam by three-streams powder feeding system. Composite coatings were prepared to increase the durability of agricultural tools. The coatings were prepared on B27 boron steel. This steel grade is most often used into produce the tools for soil cultivation. Stellite-6/WC coatings were produced using laser beam power 550 W, feed rate 400 mm/min and powder feed rate 10 g/min. Durability tests of agricultural tools were carried out by two methods. Measurement the mass loss was the first method, while measurement the tools shape using GOM ATOS II optical scanner was the second method. It was found that Stellite-6/WC coatings contributed to increase durability of agricultural tools applied for soils cultivation.

Laser cladding of phosphor bronze

磷青铜的激光熔覆

Surface and Coatings Technology, Volume 313, 15 March 2017, Pages 248-254

F. Arias-González, J. del Val, R. Comesaña, J. Penide, F. Lusquiños, F. Quintero, A. Riveiro, M. Boutinguiza, J. Pou

Abstract：Phosphor bronze is a suitable bearing material because of its good fatigue strength and excellent wear properties under corrosive conditions, high temperatures and high loads. Bronze is usually continuously cast as bar or tube and machined into bushes, cam followers, washers or other bearing components. It is common to mount bronze bushes around shafts by means of warm shrink fitting. Laser Cladding is a manufacturing process to generate a dense a metallurgical bonded coating over a substrate and it can be employed to deposit a phosphor bronze coating directly over a shaft improving its wear properties. In this paper, the feasibility of the Laser Cladding to produce phosphor bronze coatings on alloy steel is demonstrated. Suitable processing parameters to generate phosphor bronze coatings are presented. The hardness of the bronze coating obtained is 172 ± 12 HV, 56% higher than the one reported for cast bronze. Finally, Laser Cladding is proposed as a method to create a bronze surface in an area of a shaft as a substitute of warm shrink fitting of machined bronze bushes.

Online assessment of TiC decomposition in laser cladding of metal matrix composite coating

激光熔覆金属基复合材料涂层TiC分解在线评估

Materials & Design, Volume 121, 5 May 2017, Pages 310-320

Gopinath Muvvala, Debapriya Patra Karmakar, Ashish Kumar Nath

Abstract：Decomposition of ceramic particles in metal matrix composite coatings developed by laser cladding process is one of the major problems that deteriorate the mechanical properties of coating. Further, a large number of process parameters involved in laser cladding makes the process optimization difficult. Therefore, a study was undertaken to assess the condition of TiC particles in the molten pool by monitoring the thermal history using an IR pyrometer. It was observed that with the increase of molten pool lifetime, a reaction layer is created between TiC particles and metal matrix which improves their bonding. However, with further increase in the molten pool lifetime TiC particles were found to decompose completely forming dendritic structure in the metal matrix through heterogeneous nucleation and subsequent crystallization during the solidification process. This results in a change of the solidification shelf slope which can be used as an effective signature to assess the TiC particle condition in molten pool online without performing any destructive test. The modified structure of metal matrix exhibited brittle nature which increased the wear rate due to fracture and spalling of coating during the wear test.