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The effect of Nb on microstructure, mechanical, and corrosion behavior of low Mn, microalloyed δ‐TRIP steel; a comparative study
Author(s) -
Gholami Shiri Sajad,
Rahsepar Mansor,
Jahromi Seyed Ahmad,
Hayatdavoudi Hadis,
de Monlevade Eduardo Franco,
Palizdar Yahya
Publication year - 2019
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201810425
Subject(s) - materials science , corrosion , metallurgy , microstructure , ductility (earth science) , alloy , trip steel , electrochemistry , ultimate tensile strength , microalloyed steel , martensite , austenite , electrode , creep , chemistry
The aim of the present study was to examine the feasibility of achieving a better combination of yield strength, ductility, and corrosion resistance of δ‐TRIP steel through the concept of microalloying. Three δ‐TRIP steels with different contents of Nb (0, 0.025, 0.076 wt%) were subjected to the microstructural, mechanical, and electrochemical examination. ASTM A283 and ASTM A516 steels were taken as comparative samples. The obtained results revealed a threefold increase in strength × ductility products of TRIP steels (35 255 MPa%) than comparative samples (12 760 MPa%) due to the TRIP effect and multiphase nature of the TRIP steel. The addition of Nb to the TRIP steel led to an unexpected decrease in the ultimate strength (from 1167 to 955 MPa) but an increase in ductility (from 30.21 to 31.78%) and corrosion resistance. The results of the electrochemical measurements showed that while A516 alloy exhibited the lowest corrosion resistance, the corrosion resistance of TRIP specimens was significantly increased by the addition of Nb which resulted in enhancement of the charge transfer resistance of the steel and indicates the superior corrosion resistance of the steel with 0.076% Nb.