Determination of elastic modulus and residual stress of plasma-sprayed tungsten coating on steel substrate

Abstract

Plasma-sprayed tungsten, which is a candidate material for the first wall armour, shows a porous, heterogeneous microstructure. Due to its characteristic morphology, the properties are significantly different from those of its dense bulk material. Measurements of the elastic modulus of this coating have not been reported in the literature. In this work YoungÕs modulus of highly porous plasma-sprayed tungsten coatings deposited on steel (F82H) substrates was measured. For the fabrication of the coating system the vacuum plasma-spray process was applied. Measurements were performed by means of three-point and four-point bending tests. The obtained modulus values ranged from 53 to 57 GPa. These values could be confirmed by the test result of a detached coating strip, which was 54 GPa. The applied methods produced consistent results regardless of testing configurations and specimen sizes. The errors were less than 1%. Residual stress of the coating was also estimated.

Best Paper in Journal of Thermal Spray Technology: 3D Analysis in Microstructure of Thermal Spray Coatings

“…Study is currently in progress to meet this objective. A typical value for the Young's Modulus should be then around 90 GPa as obtained experimentally with bending test method [21]. Further study should cover also a statistical study of the elementary volume for calculations to be significant actually.…”

Effect of remelting process on characterization of air-plasma sprayed Fe67.5Ni23.5B9 alloy coatings onto 1Cr18Ni9Ti stainless steel

“…7a and c present that though relative compact coatings can be achieved by the air-plasma spray procedure, obvious arc voids, oxides, interfaces and loose joints exist in the coatings. According to You et al (2006), plasma-sprayed coatings usually show a porous, heterogeneous microstructure. The pores have fairly irregular shapes and a wide size distribution often exhibiting conjoining neighboring pores.…”

“…E-mail address: ywfcyy@163.com (W. Yang). coatings can be prepared onto substrate surfaces, such as the tungsten shielding coating (You et al, 2006;Davis et al, 1996;Riccardi et al, 2006), B 4 C shielding coatings on stainless steel substrate (Greuner et al, 2004;Yi Zeng et al, 2001), etc. In this work, Fe-Ni-B (Fe 67.5 Ni 23.5 B 9 , wt.…”

Interface strength measurement of tungsten coatings on F82H substrates

“…The VPS technique results in a lower tungsten density, q, and a lower Young's modulus, E, and thus the material properties used in the analysis of the VPS W-coatings are for 80% dense material properties [1,6]. For the HIP technique the density of the W-coatings does not change much and thus the material properties are those of bulk W. …”