Nano-indentation investigation on the mechanical stability of individual austenite in high-carbon steel

Journal Article · Tue Dec 15 04:00:00 EST 2015 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2015.10.024· OSTI ID:22587060

Qiao, Xun; Han, Lizhan; Zhang, Weimin; Gu, Jianfeng

Quenching (AQ) and cryogenic treatments (QC) were conducted on the high-carbon SAE 52100 steel to investigate the mechanical stability of individual retained austenite (RA) by nano-indentation. The cross-sections of indented RA region prepared by focused ion beam (FIB) were examined by using transmission electron microscopy (TEM). For the first time, it was directly observed that some parts of RA grain, closest to the indent, in AQ specimen had transformed into strain-induced martensite (SIM). However, not any pop-in or transformation was detected in the indented QC specimen. This clearly indicates that the mechanical stability of RA in QC seems significantly enhanced, which is mainly attributed to the cryogenic treatment resulting in a higher carbon enrichment of RA compared to that in AQ. Furthermore, a higher load of external stress may need to trigger its martensitic transformation in QC specimen. - Highlights: • Mechanical stability of retained austenite was studied by nano-indentation and TEM. • The strain-induced martensite transformation in RA was observed under applied load. • Cryogenic treatment enhances mechanical stability of RA due to carbon enrichment.

• OSTI ID: 22587060
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 110; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
AUSTENITE
CARBON
CARBON STEELS
ION BEAMS
ION MICROPROBE ANALYSIS
MARTENSITE
MARTENSITIC STEELS
QUENCHING
TRANSMISSION ELECTRON MICROSCOPY