Effects of electroplated zinc-nickel alloy coatings on the fatigue strength of AISI 4340 high strength steel
MetadataShow full item record
It is well known that fatigue behaviour is an important parameter to be considered in mechanical components subjected to constant and variable amplitude loadings. In combination with corrosion phenomenon, fatigue effects were responsible for proximally 64% of fails that occur in metallic parts of aeronautical accidents in the last 30 years. Recovered substrates have been extensively used in the aerospace field. Cadmium electroplating has been widely applied to promote protective coatings in aeronautical components, resulting in excellent corrosion protection combined with a good performance in cyclic loading. Ecological considerations allied to the increasing demands for corrosion resistance, resulted in the search for possible alternatives. Zinc-nickel alloys received considerable interest recently, since these coatings showed some advantages such as a good resistance to white and red rust, high plating rates and acceptation in the market. In this study the effects of zinc-nickel coatings electroplated on AISI 4340 high strength steel were analysed on rotating bending and axial fatigue strength, corrosion and adhesion resistance. Compressive residual stress field was measured by a X-ray tensometry prior to fatigue tests. Optical microscopy images showed coating thicknesses, adhesion and the existence of an uniform coverage of nearly all substrates. The fractured fatigue specimens were investigated using a scanning electron microscope. Three different zinc-nickel coating thicknesses were tested and comparison with rotating bending fatigue data from specimens cadmium electroplated and heat treated at 190°C for 3, 8 and 24 hours to avoid the diffusion of hydrogen in the substrate, was performed. Experimental results showed effect of coatings on the AISI 4340 steel behaviour when submitted to fatigue testing and the existence of coating thickness influence on the fatigue strength.
How to cite this document
Showing items related by title, author, creator and subject.
An investigation of electrolytic surface damages and electroplated crhomium effects on fatigue behavior of high strength steel De Amorim, Carlos Eduardo Silva ; Voorwald, Herman Jacobus Cornelis ; Dos Santos Vieira, Luiz Fábio; Pigatin, Walter Luis (SAE Technical Papers, 2001) [Trabalho apresentado em evento]Fatigue crack initiation occurs at the surface, although sub surface nucleation has also been reported. Localized imperfections like inclusions close to surface and surface small pits can result in crack sources. Coatings ...
Laurito, D. F.; Baptista, C. A R P; Torres, M. A S ; Abdalla, A. J. (Procedia Engineering, 2010) [Trabalho apresentado em evento]Thermal transformations on microalloyed steels can produce multiphase microstructures with different amounts of ferrite, martensite, bainite and retained austenite. These different phases, with distinct morphologies, are ...
Botelho, Edson Cocchieri ; Mazur, Rogério Lago ; Costa, Michelle Leali ; Cândido, Geraldo Maurício; Rezende, Mirabel Cerqueira (Journal of Aerospace Technology and Management, 2009) [Artigo]Aramid fiber reinforced polymer composites have been used in a wide variety of applications, such as aerospace, marine, sporting equipment and in the defense sector, due to their outstanding properties at low density. The ...