TY - JOUR

T1 - The Role of Phase Hardness Differential on the Non-uniform Elongation of a Ferrite-Martensite Dual Phase Steel

AU - Basu, Soudip

AU - Jaya, Balila Nagamani

AU - Patra, Anirban

AU - Ganguly, Sarbari

AU - Dutta, Monojit

AU - Hohenwarter, Anton

AU - Samajdar, Indradev

N1 - Publisher Copyright: © 2021, The Minerals, Metals & Materials Society and ASM International.

PY - 2021/9

Y1 - 2021/9

N2 - This study involved a commercial hot-rolled dual-phase (DP) steel consisting of martensite (~10 pct) and ferrite phases. The harder lath martensite was located at the grain boundaries and triple junctions of the equiaxed ferrite grains. Tempering and high-pressure torsion (HPT) were used to alter the phase hardness differential ∆H (where ΔH=HMartensite−HFerrite) of the DP. The relationship between ∆H and non-uniform elongation, εNU, or post-necking ductility under tensile deformation, was then explored. Tempering softened predominantly the martensite, while HPT increased the ferrite hardness. Both led to a reduction in ∆H. A drop in ∆H in the tempered DP resulted in a steady increase and eventual saturation in εNU. On the other hand, a ∆H decrease in the HPT specimens showed an initial increase in εNU followed by a drop. Strain analysis, with optical digital image correlation during tensile deformation of the tempered DP samples, clearly related the formation of strain localization with ∆H. In particular, severity of strain localization during necking scaled linearly with ∆H. This study thus brought out a potential relationship among the phase hardness differential (∆H), severity of strain localizations and post-necking ductility (εNU).

AB - This study involved a commercial hot-rolled dual-phase (DP) steel consisting of martensite (~10 pct) and ferrite phases. The harder lath martensite was located at the grain boundaries and triple junctions of the equiaxed ferrite grains. Tempering and high-pressure torsion (HPT) were used to alter the phase hardness differential ∆H (where ΔH=HMartensite−HFerrite) of the DP. The relationship between ∆H and non-uniform elongation, εNU, or post-necking ductility under tensile deformation, was then explored. Tempering softened predominantly the martensite, while HPT increased the ferrite hardness. Both led to a reduction in ∆H. A drop in ∆H in the tempered DP resulted in a steady increase and eventual saturation in εNU. On the other hand, a ∆H decrease in the HPT specimens showed an initial increase in εNU followed by a drop. Strain analysis, with optical digital image correlation during tensile deformation of the tempered DP samples, clearly related the formation of strain localization with ∆H. In particular, severity of strain localization during necking scaled linearly with ∆H. This study thus brought out a potential relationship among the phase hardness differential (∆H), severity of strain localizations and post-necking ductility (εNU).

UR - http://www.scopus.com/inward/record.url?scp=85112651964&partnerID=8YFLogxK

U2 - 10.1007/s11661-021-06361-y

DO - 10.1007/s11661-021-06361-y

M3 - Article

AN - SCOPUS:85112651964

VL - 52.2021

SP - 4018

EP - 4032

JO - Metallurgical and materials transactions. A, Physical metallurgy and materials science

JF - Metallurgical and materials transactions. A, Physical metallurgy and materials science

SN - 1073-5623

IS - 9

ER -