Dilatometric technique for evaluation of the kinetics of solid-state transformation of maraging steel

Viswanathan, U.K.; Kutty, T.R.G.; Ganguly, C.

doi:10.1007/bf02666270

Cited by 8 publications

(26 citation statements)

References 6 publications

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“…Similarly, kinetics of precipitation in various grades of maraging steel was investigated using differential scanning calorimetry, [4] by carrying out isothermal hardness measurements [6] and from dilation data acquired during heating and cooling. [11] Also, quantification of age hardening from hardness data was carried out in maraging steels and Ni-base superalloys, which followed the classical growth and coarsening theories. [12] The precipitation of intermetallic phases affects the low-carbon soft martensitic matrix by causing microstrain in the matrix.…”

Section: Introductionmentioning

confidence: 99%

X-Ray Diffraction Profile Analysis for Characterizing Isothermal Aging Behavior of M250 Grade Maraging Steel

Mahadevan

Jayakumar

Rao

et al. 2008

Metall Mater Trans A

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X-ray diffraction (XRD) studies were carried out to characterize aging behavior of M250 grade maraging steel samples subjected to isothermal aging at 755 K for varying durations of 0.25, 1, 3, 10, 40, 70, and 100 hours. Earlier studies had shown typical features of precipitation hardening, wherein the hardness increased to a peak value due to precipitation of intermetallics and decreased upon further aging (overaging) due to reversion of martensite to austenite. Intermetallic precipitates, while coherent, are expected to increase the microstrain in the matrix. Hence, an attempt has been made in the present study to understand the microstructural changes in these samples using XRD line profile analysis. The anisotropic broadening with diffraction angle observed in the simple Williamson-Hall (WH) plot has been addressed using the modified WH (mWH) approach, which takes into account the contrast caused by dislocations on line profiles, leading to new scaling factors in the WH plot. The normalized mean square strain and crystallite size estimated from mWH have been used to infer early precipitation and to characterize aging behavior. The normalized mean square strain has been used to determine the Avrami exponent in the Johnson-Mehl-Avrami (JMA) equation, which deals with the kinetics of precipitation. The Avrami exponent thus determined has matched well with values found by other methods, as reported in literature.

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Section: Introductionmentioning

confidence: 99%

X-Ray Diffraction Profile Analysis for Characterizing Isothermal Aging Behavior of M250 Grade Maraging Steel

Mahadevan

Jayakumar

Rao

et al. 2008

Metall Mater Trans A

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“…The first changes in angle slope of the line from the primary straight line portion are related to the development of the main strengthening precipitates, namely the Ni 3 Ti and Ni 3 Mo phases followed by the Fe 2 Mo or Fe 7 Mo 6 phases. The second variation at higher temperature is affected by the austenite reversion α′ → γ transition by shear and to the dissolution of precipitates [24]. The third deviation found out during measurement is a martensitic transition that occurs through the continuous cooling cycle.…”

Section: Methodsmentioning

confidence: 89%

“…Viswanathan et al [24] reported that activation energies of transitions, estimated by the Kissinger method [14], may be expressed easier to understand the form:…”

Section: Resultsmentioning

confidence: 99%

“…Common applications embrace thermal expansion, annealing studies, determination of phase transformations and the glass transition, softening points, kinetics studies, development of phase diagrams, including the determination of sintering temperature, sintering step and rate-controlled sintering. The phase transitions taking place in the continuous cooling process or the isothermal plateau is indicated by the determined difference of length [14,15,18,19,[22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

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The phase transitions in selective laser-melted 18-NI (300-grade) maraging steel

Król

Snopiński

Czech

2020

J Therm Anal Calorim

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Dilatometric studies in 18-Ni steel components fabricated by selective laser melting technique were carried out to determine the influence of heating rate on transitions occurring during the heating cycle. SLM components have been examined in controlled heating and cooling cycles. For analysis, heating of the analysed materials was carried out at heating rates of 10, 15, 20, 30 and 60 °C min −1 . During the heating process, two solid-state reactions were identified-i.e. precipitation of intermetallic phases and the reversion of martensite to austenite. A simplified procedure based on the Kissinger equation was used to determine the activation energy of individual reactions. For precipitation of intermetallic phases, the activation energy was estimated 301 kJ mol −1 , while the martensite to austenite reversion was determined at the activation energy 478 kJ mol −1 .Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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“…The detail of electrolytic cell and isolation process were present else where 12. The dried isolated and collected precipitates were analyzed using XRD technique to determine the type of the present carbides and/or carbo‐nitrides 13–16…”

Section: Experimental Workmentioning

confidence: 99%

Precipitation Behavior of Modified as Cast High Nitrogen Super Hard High‐Speed Tool Steel

Halfa

Mattar

Eissa

2012

steel research int.

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The properties of high‐speed tool steels can be improved by modifying their chemical composition or the technology of production. Nitrogen alloying is an attractive technology to enhance the mechanical and physical properties of tool steels. In this work, modified super hard high‐speed tool steel was produced through nitrogen alloying and decreasing the level of cobalt content in investigated steels. This work aims to study the effect of nitrogen as alloying element on carbides and carbo‐nitrides precipitates type, shape, and size for investigated steels. From the results obtained from Thermo‐Calc, it was concluded that nitrogen alloying produced large amount of stable austenite, also eutectic carbides precipitates (M6C and M7C3) were stable at room temperature. Transmission electron microscope (TEM) images for traditional grade showed that the as cast structure contains beside the carbides network other single carbides precipitates. While on the other hand the selected area diffraction pattern (SADP) images of nitrogen alloyed grade shows fine carbides and carbo‐nitrides precipitates with more amount of retained austenite in the ferrite matrix, they showed also the presence of the eutectic precipitates as well as the dislocations.

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Dilatometric technique for evaluation of the kinetics of solid-state transformation of maraging steel

Cited by 8 publications

References 6 publications

X-Ray Diffraction Profile Analysis for Characterizing Isothermal Aging Behavior of M250 Grade Maraging Steel

X-Ray Diffraction Profile Analysis for Characterizing Isothermal Aging Behavior of M250 Grade Maraging Steel

The phase transitions in selective laser-melted 18-NI (300-grade) maraging steel

Precipitation Behavior of Modified as Cast High Nitrogen Super Hard High‐Speed Tool Steel

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