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Infuence of matrix and alloying on the fatigue crack propagation and fracture toughness of compacted graphite iron for cylinderheads

The constants modernization in the fuels used request improvements in the combustioneffectiveness, as a consequence the material for components as the cylinder heads mustenhance their properties. Seven different compositions of compacted graphite iron (CGI)are analysed with the aim of characterized and select the most suitable material for thecylinder head service condition. The present master thesis report focuses on the impactof the matrix- either pearlitic or ferritic- and alloying elements such as molybdenum andnickel in the fatigue crack propagation ratedadNand fracture toughness (kIc).Tests to determined the fatigue crack growth rate, according to the ASTM standardE647 and fracture toughness (ASTM E399) were conducted. The equipment utilized was aservo hydraulic machine, for the fatigue crack propagation rate test and a electromechanicalmachine for the fracture toughness. Moreover, for measure the crack length a portablemicroscope camera and a camera connected to a DIC(digital image correlation) softwarewas used. The interpretation of the data obtained from the tests were done by TEMA- aDIC software- and MATLAB.The test results are analysed describing the influence of the composition and the microstructurehave over the mechanical properties achieved. Furthermore, an analyse forrelating the graphite average length and the hardness with the fatigue crack growth rateand the fracture toughness of the materials is performed.

Identiferoai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-170829
Date January 2020
CreatorsGonzalez, Leny
PublisherLinköpings universitet, Konstruktionsmaterial
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeStudent thesis, info:eu-repo/semantics/bachelorThesis, text
Formatapplication/pdf
Rightsinfo:eu-repo/semantics/openAccess

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