TY - JOUR
T1 - Impact of Si and Al on Microstructural Evolution and Mechanical Properties of Lean Medium Manganese Quenching and Partitioning Steels
AU - Kaar, Simone
AU - Krizan, Daniel
AU - Schneider, Reinhold
AU - Sommitsch, Christof
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Herein, the investigation of the tensile behavior of lean medium Mn Quenching and Partitioning (Q&P) steels containing 0.2 wt% C, 4.5 wt% Mn, and additions of 1.5 wt% Si or 1.3 wt% Al is concentrated upon. By the variation of the quenching temperature (TQ), different volume fractions of primary martensite (α′prim) are adjusted, influencing the subsequent microstructural evolution during Q&P processing. Using scanning electron microscopy (SEM), the final microstructure consisting of tempered martensite (α″), retained austenite (RA), partially bainitic ferrite (αB), and final martensite (α′final) is characterized. Furthermore, interrupted tensile tests at gradually increased strains are conducted to investigate the stability of RA against strain-induced martensite transformation (SIMT) and overall tensile behavior of lean medium Mn Q&P steels. The investigations manifest the formation of larger amounts of αB and consequently lower RA contents, when Si is substituted by Al. As an aftermath, the tendency to form α′final is significantly lower, compared with the Si-alloyed composition, reflected in the overall stress–strain behavior. Especially in case of the Si-alloyed samples containing RA fractions exceeding 15 vol%, an over-accelerated SIMT is observed, inducing failures occurring prior to necking, whereas for the Al-alloyed samples, a wider process window is obtained.
AB - Herein, the investigation of the tensile behavior of lean medium Mn Quenching and Partitioning (Q&P) steels containing 0.2 wt% C, 4.5 wt% Mn, and additions of 1.5 wt% Si or 1.3 wt% Al is concentrated upon. By the variation of the quenching temperature (TQ), different volume fractions of primary martensite (α′prim) are adjusted, influencing the subsequent microstructural evolution during Q&P processing. Using scanning electron microscopy (SEM), the final microstructure consisting of tempered martensite (α″), retained austenite (RA), partially bainitic ferrite (αB), and final martensite (α′final) is characterized. Furthermore, interrupted tensile tests at gradually increased strains are conducted to investigate the stability of RA against strain-induced martensite transformation (SIMT) and overall tensile behavior of lean medium Mn Q&P steels. The investigations manifest the formation of larger amounts of αB and consequently lower RA contents, when Si is substituted by Al. As an aftermath, the tendency to form α′final is significantly lower, compared with the Si-alloyed composition, reflected in the overall stress–strain behavior. Especially in case of the Si-alloyed samples containing RA fractions exceeding 15 vol%, an over-accelerated SIMT is observed, inducing failures occurring prior to necking, whereas for the Al-alloyed samples, a wider process window is obtained.
KW - lean medium Mn Q&P steels
KW - retained austenite stabilities
KW - stress–strain behaviors
UR - http://www.scopus.com/inward/record.url?scp=85088446597&partnerID=8YFLogxK
U2 - 10.1002/srin.202000181
DO - 10.1002/srin.202000181
M3 - Article
AN - SCOPUS:85088446597
SN - 1611-3683
VL - 91
SP - 1
EP - 7
JO - steel research international
JF - steel research international
IS - 10
M1 - 2000181
ER -