Change in the Morphology of the Surface of Ta–W Coating after Exposure to Cyclic Laser Pulses
- Authors: Karnavskaya T.G.1, Kikin P.Y.2, Perevezentsev V.N.2,3, Razov E.N.2,3, Rusin E.E.2
- 
							Affiliations: 
							- Central Scientific Research Institute Burevestnik
- Mechanical Engineering Research Institute, Russian Academy of Sciences
- Lobachevsky State University of Nizhny Novgorod
 
- Issue: Vol 10, No 3 (2019)
- Pages: 578-581
- Section: Functional Coatings and Surface Treatment
- URL: https://journals.rcsi.science/2075-1133/article/view/207919
- DOI: https://doi.org/10.1134/S2075113319030146
- ID: 207919
Cite item
Abstract
The effect of low-energy pulsed laser irradiation (laser LRS-150A, λ = 1.06 μm) on the surface of Ta–10% W coating produced by ion-plasma deposition in vacuum was investigated. The coating thickness was ~250 μm. With the help of the metallography method, it was shown that the coating average grain size was ~25 μm. The laser pulse energy was 30 J, pulse duration τ = 14 × 10–3 s, and the interval between laser pulses was 7.5 s. The laser beam was focused on the sample surface into a spot with a diameter of 5 mm. The microrelief of the coating surface was investigated with the use of a TESCAN VEGA II scanning electron microscope. X-ray microanalysis in the scanning line of the surface and cross section of the coating and the substrate was carried out on an INCA Energy 250 energy dispersive spectrometer. It was shown that, after a multicycle laser irradiation (200 pulses), numerous rounded protrusions appeared on the surface of the coating. The diameter of the protrusions ranged from 25 to 225 μm and their maximum height was 30 μm. In the irradiation zone, redistribution of W occurred. The concentration of W in the region of the protrusions decreased substantially and increased in the ranges between the protrusions. It was concluded that the appearance of protrusions on the surface of irradiated surface could be due to the simultaneous occurrence of several interdependent processes, such as the loss of stability of the coating with the formation of alternating areas of tensile and compressive stresses, diffusion of tungsten into the regions of compressive stresses, and relaxation of internal stresses by grain-boundary sliding with extrusion of grains and their conglomerates on the surface.
About the authors
T. G. Karnavskaya
Central Scientific Research Institute Burevestnik
							Author for correspondence.
							Email: karnavskaya.tanya@burevestnik.com
				                					                																			                												                	Russian Federation, 							Nizhny Novgorod, 603950						
P. Yu. Kikin
Mechanical Engineering Research Institute, Russian Academy of Sciences
														Email: eerusin@mail.ru
				                					                																			                												                	Russian Federation, 							Nizhny Novgorod, 603024						
V. N. Perevezentsev
Mechanical Engineering Research Institute, Russian Academy of Sciences; Lobachevsky State University of Nizhny Novgorod
							Author for correspondence.
							Email: v.n.perevezentsev@gmail.com
				                					                																			                												                	Russian Federation, 							Nizhny Novgorod, 603024; Nizhny Novgorod, 603098						
E. N. Razov
Mechanical Engineering Research Institute, Russian Academy of Sciences; Lobachevsky State University of Nizhny Novgorod
														Email: eerusin@mail.ru
				                					                																			                												                	Russian Federation, 							Nizhny Novgorod, 603024; Nizhny Novgorod, 603098						
E. E. Rusin
Mechanical Engineering Research Institute, Russian Academy of Sciences
							Author for correspondence.
							Email: eerusin@mail.ru
				                					                																			                												                	Russian Federation, 							Nizhny Novgorod, 603024						
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