Structure and Fatigue Properties of Cr-Ni-Ti Austenitic Steel after Equal Channel Angular Pressing

Abstract:

After equal channel angular pressing (ECAP) at room temperature in 08%C-18%Cr-10%Ni-Ti steel grain-subgrain structure with the size of structural elements of 100-250 nm, volume of high angle boundaries (HAB) about 59% and 38% of martensite is formed. ECAP at 400°C results in fully austenitic structure with the structural element size of 100-400 nm and volume of HAB ~54%. ECAP increases the ultimate tensile strength of 08%C-18%Cr-10%Ni-Ti steel by 1.5 - 2 times, the yield stress by 3.8 - 5.2 times, the fatigue limit - by 1.4 - 1.7 times, however the ductility is reduced. Fatigue strength is enhanced by the refinement of the structure and twinning in the austenite during ECAP and due to intensive dynamic twinning, partial martensitic transformation and increasing of the volume of HAB during cyclic deformation.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 2611-2616
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.2611
• Online since: May 2014
• Authors: Sergey V. Dobatkin*, Werner Skrotzki, Vladimir Terent’ev, Olga Rybalchenko, Andrey Belyakov, Dmitry Prosvirnin, Eugenie Zolotarev
• Keywords: Twinning, Austenite, Equal-Channel Angular Pressing (ECAP), Fatigue, Martensite, Stainless Steel (SS), Strength, Ultra-Fine Grained Structure

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