2024-03-29T12:13:59Z
https://soar-ir.repo.nii.ac.jp/oai
oai:soar-ir.repo.nii.ac.jp:00012311
2022-12-14T04:05:54Z
1221:1222
Effects of Microalloying on the Impact Toughness of Ultrahigh-Strength TRIP-Aided Martensitic Steels
Kobayashi, Junya
Ina, Daiki
Nakajima, Yuji
Sugimoto, Koh-Ichi
The effects of the addition of Cr, Mo, and/or Ni on the Charpy impact toughness of a 0.2 pct C-1.5 pct Si-1.5 pct Mn-0.05 pct Nb transformation-induced plasticity (TRIP)-aided steel with a lath-martensite structure matrix (i.e., a TRIP-aided martensitic steel or TM steel) were investigated with the aim of using the steel in automotive applications. In addition, the relationship between the toughness of the various alloyed steels and their metallurgical characteristics was determined. When Cr, Cr-Mo, or Cr-Mo-Ni was added to the base steel, the TM steel exhibited a high upper-shelf Charpy impact absorbed value that ranged from 100 to 120 J/cm2 and a low ductile–brittle fracture appearance transition temperature that ranged from 123 K to 143 K (−150 °C to −130 °C), while also exhibiting a tensile strength of about 1.5 GPa. This impact toughness of the alloyed steels was far superior to that of conventional martensitic steel and was caused by the presence of (i) a softened wide lath-martensite matrix, which contained only a small amount of carbide and hence had a lower carbon concentration, (ii) a large amount of finely dispersed martensite-retained austenite complex phase, and (iii) a metastable retained austenite phase of 2 to 4 vol pct in the complex phase, which led to plastic relaxation via strain-induced transformation and played an important role in the suppression of the initiation and propagation of voids and/or cleavage cracks.
Article
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE. 44A(11):5006-5017 (2013)
journal article
SPRINGER
2013-11
application/pdf
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
11
44A
5006
5017
1073-5623
AA10987657
https://soar-ir.repo.nii.ac.jp/record/12311/files/Effects_of_Microalloying_on_the_Impact_Toughness.pdf
eng
10.1007/s11661-013-1882-9
https://doi.org/10.1007/s11661-013-1882-9
The final publication is available at www.springerlink.com