Comparison of two new surface treatment processes, laser-induced shock waves and primary explosive: application to fatigue behaviour

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 1992-08, Vol.156 (2), p.175-182
• Main Authors: Gerland, M., Hallouin, M., Presles, H.N.
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Metals. Metallurgy; Other surface treatments; Production techniques; Surface treatment
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/0921-5093(92)90149-U

Two surface treatment processes, the one by laser-induced shock waves, the other by primary explosive, have been used on a 316 L type stainless steel in order to improve fatigue behaviour. In spite of very different shock characteristics (18 GPa, 0.6 ns for the laser treatment and 1.5 GPa, 1 μs for the explosive treatment), the microstructures and the microhardness profiles are rather similar. The significant increase of microhardness in the first 50 μm in depth is associated with a high twin density. The fatigue behaviour of the two treated samples is characterized by very high cyclic stresses during the whole cycling and slightly shorter fatigue lives than in the untreated material. The surface of the treated samples exhibits more considerable secondary microcrack density than the untreated material because of the high twin density of the near surface treated layers.