Multiple strengthening sources and adiabatic shear banding during high strain-rate deformation of AISI 321 austenitic stainless steel: Effects of grain size and strain rate

Metastable Austenitic Steel Structure and Mechanical Properties Evolution in the Process of Cold Radial Forging

“…However, a noticeable increase in the amount of the α-phase due to the formation of deformation-induced α′-martensite is observed after e = 0.56. Further deformation leads to a significant acceleration of the γ → α′ transformation due to an increasing number of areas of predominant formation of α′-martensite embryos—deformation twins, shear bands and grain boundaries [3]. Furthermore, Figure 4b shows an approximating sigmoidal curve, which will be discussed in Section 4.…”

“…It should be noted that significant structural changes occur as a part of this process. These changes are associated with the glide of dislocations, strain-induced twinning, formation of shear bands, precipitation or dissolution of particles, strain-induced martensitic transformation (SIMT), rotation of substructure elements and recrystallization [1,2,3]. Features of the mechanisms of structure formation during deformation of metastable austenite depend primarily on the temperature relationship of the stacking fault energy (SFE) and the crystallographic orientation of the crystals relative to the loading axis.…”

“…However, in the case of deformation with relatively low degrees at a constant temperature, when the development of SIMT and twinning is simultaneously possible, the mechanism of deformation in each grain is determined primarily by its orientation relative to the loading axis [6]. During deformation of MASS with different degrees, the process of structure formation can be divided into stages due to the implementation of various deformation mechanisms [3,7,8,9], which has a decisive influence on the mechanical properties of MASS.…”

“…At present, the processes of formation of structure and properties during cold plastic deformation of MASS by rolling [8,10,11], torsional deformation [12], surface mechanical attrition treatment [13] and equal-channel angular pressing [14,15,16] have been the most commonly studied processes. These methods of strain hardening differ in the strain pattern and rate, which, as is well known, significantly affect the processes of structure formation during deformation processing, and consequently the properties of the processed steel [3,13,17,18,19]. However, structural changes and their impact on the formation of a complex of mechanical properties of MASS during cold radial forging (CRF) are currently understudied.…”

Structure–Property Correlation and Constitutive Description of Structural Steels during Hot Working and Strain Rate Deformation

“…It is fully understood that smaller grain size leads to an increase in the grain boundaries in the metal matrix. These grain boundaries, in turn, provide a restriction to the dislocation movement during plastic deformation and thus lead to an increase in the strength of the material [69][70][71][72]. The Zener Holloman parameter [73][74][75] is mostly used to predict the resulting grain size (Z = ε ėxp(Q/RT)), and the size of the recrystallized ferrite (d) is mathematically expressed in terms of the Z parameter as follows:…”