The Study of Structure Formation Evolution at High Pressure with a Shear in a Corrosion-Resistant Austenitic-Ferritic Steel 03Kh14N10K5M2YuT with Different Initial States

The article presents results of studies of phase transformations and structure formation that form the necessary complex of physical and mechanical properties of austenitic-ferritic steel with a structural ratio of 50:50. The structure formation at high pressure with a shear of steel 03Kh14N10K5M2YuT with different initial states is studied. After the action of intense plastic deformations, a submicrocrystalline structure arises. This causes interest in these deformations.

Kinetics of Submicrocrystalline Structure Formation in a Cu-Cr-Zr Alloy during Large Plastic Deformation

The grain refinement and kinetics of submicrocrystalline structure formation in a Cu-0.3%Cr - 0.5%Zr alloy during large plastic deformation were investigated. The fraction of high-angle boundaries and the fraction of ultrafine grains were used to estimate the kinetics of grain refinement and submicrocrystalline structure evolution during large plastic deformation. The multidirectional forging (MDF), equal channel angular pressing (ECAP), and high pressure torsion (HPT) were used as methods of large plastic deformation. Comparative analysis showed that the grain refinement process occurred faster during HPT and MDF in comparison with ECAP. The fraction of ultrafine grains achieved almost 1 after 3 HPT turns and after MDF to the total strain of 4; while the one reached only 0.29 after 4 ECAP passes. The modified Johnson-Mehl-Avrami-Kolmogorov equation could be applied to determine the kinetics of grain refinement in copper alloy during large plastic deformation as a function of true strain.

Submicrocrystalline Austenitic Stainless Steel Processed by Cold or Warm High Pressure Torsion

The formation of submicrocrystalline structure during severe plastic deformation and its effect on mechanical properties of an S304H austenitic stainless steel with chemical composition of Fe – 0.1C – 0.12N – 0.1Si – 0.95Mn – 18.4Cr – 7.85Ni – 3.2Cu – 0.5Nb – 0.01P – 0.006S (all in mass%) were studied. The severe plastic deformation was carried out by high pressure torsion (HPT) at two different temperatures, i.e., room temperature or 400°C. HPT at room temperature or 400°C led to the formation of a fully austenitic submicrocrystalline structure. The grain size and strength of the steels with ultrafine-grained structures produced by cold or warm HPT were almost the same. The ultimate tensile strengths were 1950 MPa and 1828 MPa after HPT at room temperature and 400°C, respectively.