Brittle fracture of high-strength steels at very low temperatures |
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Authors: | R RODRÍGUEZ-MARTÍN I OCAÑA A MARTÍN-MEIZOSO |
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Affiliation: | CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián, Spain |
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Abstract: | High-strength steels are used to increase the load carrying capacity of components. However, to guarantee a safe design, it is also necessary to combine high strength with adequate fracture toughness. In this paper, fracture toughness of three high-strength steels with yield strengths ranging from 460 to 890 MPa has been studied at very low temperatures. Taking into account experimental evidence, a new mechanism of cleavage at very low temperatures is proposed. This mechanism considers the possibility of reaching the ideal strength (the stress at which the lattice of a single crystal losses its stability) in the immediate vicinity of the fatigue crack tip. Moreover, a computational model able to calculate the external load needed to produce a catastrophic failure of these steels has been developed. |
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Keywords: | cleavage high-strength steels ideal strength toughness |
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