Quantitative analysis of the influence of strain hardening on equal channel angular pressing process

Ultrafine grained (UFG) ferrite-martensite dual phase steels were fabricated by equal channel angular pressing and subsequent intercritical annealing. Their room temperature tensile properties were examined and compared to those of coarse grained counterpart. The formation of UFG martensite islands of ~ 1 μm was not confined to the former pearlite colonies but they were uniformly distributed throughout UFG matrix. The strength of UFG dual phase steels was much higher than that of coarse grained counterpart but uniform and total elongation were not degraded. More importantly, unlike most UFG metals showing negligible strain hardening, the present UFG dual phase steels exhibited extensive rapid strain hardening.

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Use of the Thixomet PRO software for quantitative analysis of the ultrafine-grain structure of low-and medium-carbon steels subjected to equal channel angular pressing

Metal Science and Heat Treatment ◽

10.1007/s11041-012-9518-z ◽

2012 ◽

Vol 54 (7-8) ◽

pp. 387-392 ◽

Cited By ~ 11

Author(s):

N. V. Koptseva ◽

M. V. Chukin ◽

O. A. Nikitenko

Keyword(s):

Quantitative Analysis ◽

Equal Channel Angular Pressing ◽

Carbon Steels ◽

Grain Structure ◽

Ultrafine Grain ◽

Medium Carbon ◽

Angular Pressing ◽

Medium Carbon Steels ◽

Ultrafine Grain Structure ◽

Thixomet Pro Software

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Effects of strain hardenability and strain-rate sensitivity on the plastic flow and deformation homogeneity during equal channel angular pressing

Journal of Materials Research ◽

10.1557/jmr.2001.0113 ◽

2001 ◽

Vol 16 (3) ◽

pp. 856-864 ◽

Cited By ~ 78

Author(s):

Hyoung Seop Kim ◽

Sun Ig Hong ◽

Min Hong Seo

Keyword(s):

Strain Rate ◽

Strain Hardening ◽

Plastic Flow ◽

Equal Channel Angular Pressing ◽

Strain Rate Sensitivity ◽

Rate Sensitivity ◽

Strain Hardening Exponent ◽

Angular Pressing ◽

Deformation Inhomogeneity ◽

Method Analysis

The effects of strain hardenability and strain rate sensitivity on the plastic flow and deformation inhomogeneity during equal channel angular pressing were studied using a finite element method analysis. In this study, perfect plastic nonhardening and rate-insensitive materials, and rate-sensitive materials were considered. In case of the nonhardening and rate-insensitive materials, the deformed geometry was predicted to be quite uniform and homogeneous. Deformation inhomogeneity developed, however, in materials with finite work-hardening exponent and strain-rate sensitivity. The corner gap formed in strain-hardening materials whereas the upper and lower channel gaps formed in strain-rate-sensitive materials. The deformation inhomogeneity was strongly dependent on the relative effects of strain-hardening exponent and strain-rate sensitivity. The predictions on the deformation inhomogeneity and the formation of corner and channel gaps were compatible with the experimental data published in the literature.

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