• Journal of Powder Materials
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• v.26 no.5
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• pp.389-394
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• 2019

In the present study, we have investigated the effect of sintering process conditions on the stability of the austenite phase in the nanocrystalline Fe-5wt.%Mn-0.2wt.%C alloy. The stability and volume fraction of the austenite phase are the key factors that determine the mechanical properties of FeMnC alloys, because strain-induced austenite-martensite transformation occurs under the application of an external stress at room temperature. Nanocrystalline Fe-5wt.%Mn-0.2wt.%C samples are fabricated using the spark plasma sintering method. The stability of the austenite phase in the sintered samples is evaluated by X-ray diffraction analysis and hardness test. The volume fraction of austenite at room temperature increases as the sample is held for 10 min at the sintering temperature, because of carbon diffusion in austenite. Moreover, water quenching effectively prevents the formation of cementite during cooling, resulting in a higher volume fraction of austenite. Furthermore, it is found that the hardness is influenced by both the austenite carbon content and volume fraction.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.969-974
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• 1998

The effect of vanadium, which is known to decrease the stacking fault energy of Fe-base alloys, on the microstructure and elevated temperature sliding wear resistance of Fe-20Cr- 1.7C- 1Si alloy was investigated. The maximum amount of vanadium maintaining the austenitic matrix seems to be about 3wt.% in Fe-20Cr- 1.7C-1Si-xV (x = 0, 1, 3, 6. lOwt.%) alloys and the austenitic alloys showed better wear resistance than ferritic alloys. It was considered to be due to the low stacking fault energy and $\gamma->\alpha$ strain-induced phase transformation at rmm temperature. It was shown from elevated temperature sliding tests up to .$225^{\circ}C$ that the addition of vanadium increases the temperature, at which the transition from oxidative wear to adhesive wear occur, and the amount of d formed at $225^{\circ}C$. Thus, it was considered that the addition of vanadium improves the elevated temperature sliding wear resistance of Fe-20Cr- 1.7C - 1Si by reducing the increasing rate of stacking fault energy with temperature and by increasing Ma temperature.