The Effect of Preliminary Thermomechanical Processing on the Kinetics of Localized Plasticity Autowaves in Trip Steel

• Main Authors: Dina V. Orlova, Vladimir I. Danilov, Vadim V. Gorbatenko, Lidiya V. Danilova, Galina V. Shlyakhova, Lev B. Zuev
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Metals
• Subjects: TRIP steel; digital image correlation; thermomechanical processing; martensite transformation; deformation bands; autowaves
• Online Access: https://www.mdpi.com/2075-4701/10/11/1494
• ISSN: 2075-4701

The kinetics of the martensitic transformation fronts in transformation-induced plasticity (TRIP) steel was studied in relation to preliminary thermomechanical treatment using the digital image correlation method. It was found that warm rolling of steel to 40‒63% reduction significantly increases the stress of the onset of strain-induced phase transformation and changes the loading curve stages. The strain-induced phase transformation in TRIP steel occurring through the formation of Lüders and Portevin‒Le Chatelier bands is shown to be an autowave process of localized plasticity. The austenite → martensite transformation at the elastic-plastic transition occurs in the form of several switching localized plasticity autowaves. At the jerky flow stage, excitation autowaves of localized plasticity are generated and propagate repeatedly until the strain-induced austenite → martensite transformation is completed. It is shown for the first time that the sources of excitation autowaves in the material are the sites of nucleation or annihilation of switching autowaves.