Prior thermo-mechanical processing to modify structure and properties of severely deformed low carbon steel

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Zrnik, J.^1 ; Lapovok, R.^2 ; Raab, G.I.^3

Comtes FHT Inc., Prumyslova 995, Dobrany, Czech Republic^1

ARC Centre of Excellence for Design in Light Metals, DME, Monash University, Clayton, VIC 3800, Australia^2

Institute of Physics of Advanced Materials, UFA, Russia^3

关键词: Dense dislocation networks;    Increased temperature;    Severe plastic deformations;    Structure and properties;    Structure refinements;    Submicrocrystalline structures;    Tensile deformation;    Thermo-mechanical processing;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012066/pdf
DOI  :  10.1088/1757-899X/63/1/012066

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The article focuses on the severe plastic deformation (SPD) of low carbon steel AISI 1010 performed at increased temperature. The grain refinement of ferrite structure is monitored and described with respect to different initial steel structure modified by thermal and thermomechanical (TM) treatment (TM) prior severe plastic deformation. The refinement of coarse initial ferrite structure with grain size in range of 30-50 gm resulted from solutioning was conducted then in two steps. Preliminary structure refinement has been achieved due to multistep open die forging process and quite uniform ferrite structure with grain size of the order of gm was obtained. The further grain refinement steel structure was then accomplished during warm Equal Channel Angular Pressing (ECAP φ 120°) at 300°C, introducing different strain in range of ef 2.6 -4. The change of microstructure in dependence of the effective strain was evaluated by SEM and TEM study of thin foils. The high straining of steel resulted in extensive deformation of ferrite grains and formation of mixture of submicron grains structure in banded deformed structure with dense dislocation network and subgrains. The dynamic polygonization process, due to increased ECAP temperature, modified the submicrocrystalline structure formation. There was only indistinctive difference observed in structure refinement when considering different initial structure of steel. The tensile behaviour was characterized by strength increase followed by softening. None work hardening phenomenon appeared at tensile deformation of deformed bars.