Elastic properties of eta carbide (η-Fe2C) from ab initio calculations: application to cryogenically treated gear steel

Influence of the holding time of the deep cryogenic treatment on the strain hardening behavior of HY-TUF steel

“…This can be related to the precipitates thought to result from the migration of carbon atoms towards the dislocations during long holding at low temperatures. The carbon clouds around the dislocations serve as nuclei for the η-carbide, which is consistent with the previous studies by Oila et al (2014) who observed precipitates of η-carbide in the vicinity of dislocations in the DCT martensite of a low-alloy medium-carbon steel. …”

“…Higher order of microhardness values for the DCT steels compared to that of the CHT steel can be seen to imply change in the type of carbides. According to microhardness measurements on carbide phase and what is mentioned by Oila et al (2014), the carbides of DCT microstructure could be η-type with a higher order of microhardness magnitude while the carbides of CHT microstructure could be cementite. (iii) The microhardness results in Fig.…”

“…6 also indicate that the CHT steel has a greater microhardness value of martensite in comparison to those of the DCT steels. According to many studies (Chi et al 2010;Jaswin and Lal 2011;Oila et al 2014), microhardness of martensite is directionally proportional to its carbon content; thus, lower microhardness of martensite in DCT microstructures could be attributed to its lower carbon content. The decrement in carbon content of DCT martensite corroborates the idea of formation of η-carbides which absorbed more carbon atoms of martensitic matrix during the deep cryogenic process.…”

Martensitic transformation in AISI D2 tool steel during continuous cooling to 173 K

“…The effect of cryogenic treatment on microstructure evolution, wear, and mechanical properties of Fe-C steel, tool steels, and specifically AISI D2 tool steel has been previously reported by many researchers [10][11][12][13][14][15][16][17][18][19][20][21]. The temperature ranges studied by researchers varies from 223K to 77K and depending on the investigated temperature interval, the denominations are different:…”

“…Preciado and Pellizzari [10], Olia et al [12], and Das et al [19,21] have presented the most recent studies on the influence of cryogenic treatment and subsequent tempering on the sequence of precipitation of temper carbides and the evolution of mechanical and wear properties. However, in spite of the extensive amount of work, little information is available on martensite's characteristics and the kinetics of martensitic transformation during direct cooling to 173 K (shallow cryogenic temperature).…”