ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
A new variety of duplex steels with superior mechanical properties has been studied.They exhibit a very interesting combination of strength (tensile strength of 680 MPa) and ductilityvalues (more than 45% total elongation) due to the competition between different plasticitymechanisms. These steels contain two phases: austenite and ferrite and are characterized by lowstacking fault energy at room temperature. In this work, four duplex steels with different chemicalcomposition and phase volume fraction are studied. Residual and internal stresses in each phasewere determined using the classical X-ray diffraction sin²ψ method. In the as-received state, bothlongitudinal and transverse residual stresses are in compression (until -350 MPa) for the ferrite andin tension (until +410 MPa) for the austenite. However, residual stresses in the austenitic phasedecrease when its volume fraction increases. Moreover, internal stress distribution in one alloy wasdetermined by X-ray diffraction during an in situ tensile test. The austenitic phase stress along theloading direction is higher than the macroscopic applied one, which is higher than the ferritic stressstate, verifying a mixture rule and consistent with the initial residual stresses. For an appliedmacroscopic strain of about 1%, the austenite phase is subjected to a stress of about 600 MPawhereas the stress in the ferritic phase is about 300 MPa. It was also observed that as macroscopicstrain increases, stress difference between the austenite and the ferrite decreases
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.524-525.833.pdf
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