Investigation of a new shear deformation method for the production of nanostructures in low-carbon steel

Abstract

Microstructure, properties, and failure characteristics of medium-carbon steel subjected to severe plastic deformation Marina V Karavaeva, Svetlana K Kiseleva, Marina M Abramova et al. The structural parameters and the nature of distribution of the plastic deformation intensity were investigated. Higher efficiency of the drawing process with shear was revealed in terms of strain intensity accumulation. A comparative analysis of structural changes and microhardness distribution over the bulk of samples produced by the investigated methods was conducted. The repeatability of the stress-strain state parameters obtained through physical and mathematical modeling was shown. The analysis of the obtained results leads to the conclusion that the use of drawing with shear is advanced for the production of samples and billets with high strength and sufficiently high ductility by creating a gradient structure.Severe plastic deformation (SPD) is one of the most effective techniques to enhance the physical and mechanical properties of metallic materials via refining the structure to obtain the ultrafine-grained (UFG) and nanocrystalline (NC) states. For the formation of UFG and NC structures, complex deformation schemes are usually used: high pressure torsion, equal channel angular pressing, screw extrusion, etc. [1][2][3]. Despite the differences in loading conditions, all these schemes have one thing in common -the structure is refined due to active shear deformation of the metal under the combined effect of compression and tension. Further development of SPD techniques implies the elaboration of combined loading schemes with a mandatory use of shear deformation.The most well-known and widespread scheme of simple shear is free torsion [4]. Combining the scheme with reduction may be promising to disperse the structure and, as a result, to enhance mechanical properties.In recent years the methods of surface deformation treatment have been provoking interest. Among them are the known methods of forging [5], surface friction [6], ultrasonic treatment [7], and others, and also the methods developed not so long ago -ECA broaching and shear drawing [8,9].In the present paper we study the influence of two different loading schemes -conventional drawing and shear drawing -on the change in the deformation intensity and corresponding transformation of the structure that occurs in low-carbon steel under this treatment, and also to determine the relationship between these changes and mechanical characteristics.Additionally we propose here to perform an assessment of the severe plastic deformation intensity using numerical modeling, which would allow comparing the calculation results with the observed changes in the structure and properties.

Influence of Drece Method on Mechanical Properties of Different Low Carbon Steel

“…Alloys formed by SPD methods achieve an increase in plasticity, strength or toughness. At UFG alloys also show effect superplasticity [4][5][6]. One of the new type of the severe plastic deformation method is called ECAP -Conform.…”

Physical and Technical Foundations of the Use of Alternating Free Bending for Producing Long-length Semi-products from Metals and Alloys with Improved Mechanical Properties

“…Later, the effect of this factor was found on the tensor of dislocation density, an increase in the shear and rotational components of accumulated strain, grain sizes and angle misorientations [9]. The qualitative consistency between the currently developed deformation model of structure refinement in the process of SPD and the experiment served as a basis for the development of new SPD processes, including combined SPD processes [25][26][27][28], combining different types of non-monotonic strain, e.g., ECAP followed by rolling.…”