Low-temperature nitriding of 38CrMoAl steel with a nanostructured surface layer induced by surface mechanical attrition treatment

• Published in: Surface & coatings technology Vol. 202; no. 20; pp. 4957 - 4963
• Main Authors: Tong, W.P., Han, Z., Wang, L.M., Lu, J., Lu, K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-07-2008; Elsevier
• Subjects: 38CrMoAl steel; Applied sciences; Contact of materials. Friction. Wear; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Heat treatment; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nanocrystalline materials; Nitriding; Physics; Production techniques; Surface mechanical attrition treatment; Surface treatments; Thermochemical treatment and diffusion treatment; Wear resistance; 38CrMoAl steel; Surface mechanical attrition treatment; Nitriding; Wear resistance; Nanocrystalline materials; Thermochemical treatment; Temperature; Mechanical properties; Surface treatments; Nanostructures; Mechanical treatment; Wear; Nitridation; Surface layers; Nanocrystal; Low temperature; Tribology
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2008.04.085

A nanocrystalline surface layer was fabricated on a 38CrMoAl steel plate by means of a surface mechanical attrition treatment (SMAT). The average grain size in the top surface layer (10 μm thick) is about 10 nm, and the grain size stability can be maintained up to 450 °C. The effect of the surface nanocrystalline layer on the gas nitriding process at a lower temperature was investigated by using structural analysis and wear property measurements. The surface nanocrystallization evidently enhances nitriding kinetics and promotes the formation of an ultrafine polycrystalline compound layer. The results of the investigation showed that this new gas nitriding technique can effectively increase the hardness and wear resistance of the resulting surface layer in comparison with conventional nitriding, demonstrating a significant advancement for materials processing.