Interfacial Strength Evaluation of Oxide Films on Carbon Steel by Using the Laser Shock Adhesion Test
We investigate the adhesion strength (interfacial strength) of the oxide film formed on a carbon steel substrate by using a laser shock adhesion test (LaSAT). A rolled carbon steel (SS400) plate is first heated at high temperature (700 °C) under the atmosphere (heat treatment) to cause the formation of oxide films about 20-50 μm thick on the steel surface. The film consisted of multiple layers, including wustite (FeO), magnetite (Fe3O4), and hematite (Fe2O3). Next, the x-ray diffraction method was used to measure the residual stress in the film. We find that compression stress develops in the film because of a mismatch of thermal strain in between the film and substrate after the heat treatment. With LaSAT, strong elastic wave generates by a pulsed laser ablation of the substrate backside, and results in interfacial fractures in the oxide films. To monitor the normal (out-of-plane) displacement of the top surface film, a laser ultrasonic interferometer is simultaneously utilized, such that we detect film delamination and determine the critical laser energy for interfacial fracture to obtain the critical stress (interfacial strength). Furthermore, additional pulsed laser irradiation is conducted against a pre-delaminated specimen in order to examine the growth of delamination area and evaluate the interfacial fracture toughness. Finally, elastic wave propagation in the sample is computed using the finite element method (FEM) in order to evaluate the interfacial stress field, accurately. For the FEM, multiple layers in the oxide film are modeled, and the residual stress due to thermal strain mismatch is introduced. The FEM computations reveal the stress distribution around the interface and evaluate the critical stress and critical stress intensity factor for delamination. We thus quantitatively evaluate the interfacial strength and interfacial fracture toughness of the oxide film formed on carbon steel. The mechanism of interfacial fracture is also discussed on the basis of microstructures in a film with multiple layers. This result may be useful for understanding the adhesion quality of oxide film during the hot-rolling process.
Keywordsadhesion carbon steel finite element method interfacial fracture laser shock adhesion test oxide film
This work was supported by JSPS KAKENHI (Grant No. 17K06062) from the Japan Society for the Promotion of Science (JSPS) and by a research grant from JFE Twenty-first Century Foundation. A part of this work was conducted at the Advanced Characterization Nanotechnology Platform of the University of Tokyo, and supported by the “Nanotechnology Platform” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
- 2.H. Tanei and Y. Kondo, Transformation Behavior of Oxide Scale and Its Control, Nippon Steel Sumitomo Met. Tech. Rep., 2015, 401, p 91–95Google Scholar
- 4.H. Tanei and Y. Kondo, Adhesion Issue of Hot-Rolling Scale. JSMS, Committee on Corrosion and Protection (in Japanese) 2013, p. 293.2–293.52Google Scholar
- 8.H. Ito, S. Kiminami, and H. Cho, Evaluation of Adhesion Quality of Oxide Scale on Low Carbon Steel at High Temperature Using a Laser Spallation Technique, Trans. JSME, 2015, 81, p 14-00493 (in Japanese)Google Scholar
- 9.R.H. Lacombe, Adhesion Measurement Methods: Theory and Practice, CRC Press, Boca Raton, 2006Google Scholar
- 29.V. Gupta, J. Yuan, and A. Pronin, Recent Developments in the Laser Spallation Technique to Measure the Interface Strength and Its Relationship to Interface Toughness with Applications to Metal/Ceramic, Ceramic/Ceramic and Ceramic/Polymer Interfaces, J. Adhes. Sci. Technol., 1994, 8, p 713–747CrossRefGoogle Scholar
- 34.M. Boustie, E. Auroux, J.P. Romain et al., Determination of the Bond Strength of Some Microns Coatings Using the Laser Shock Technique European Physical, J. Appl. Phys., 1999, 5, p 149–153Google Scholar
- 37.J.L. Vossen, Adhesion Measurement of Thin Films, Thick Films and Bulk Coatings, Am. Soc. Test. Mater. STP, 1978, 640, p 122–133Google Scholar
- 50.S. Kobayashi, T. Urabe, H. Osawa et al., Peeling Properties of Structures Of Scale in Steel Sheet, Curr. Adv. Mater. Process. CAMP-ISIJ, 1998, 11, p 1087–1090 (in Japanese)Google Scholar
- 51.R. Yuuki and J. Xu, Mechanics of Interfacial Crack, Prod. Res., 1993, 42, p 60–66 (in Japanese)Google Scholar
- 52.J. Dundurs, Boundary Conditions at Interfaces, Micromechanics and Inhomogeneity, G.J. Weng, M. Taya, H. Abé, Ed., Springer, New York, NY, 1990, p 109–114Google Scholar