Grain boundary precipitation strengthening in high temperature creep of Fe15Cr25Ni alloys

Zhang, J.S.; Li, P.E.; Chen, W.X.; Jun-ze, Jin

doi:10.1016/0036-9748(89)90449-3

Cited by 22 publications

(5 citation statements)

References 6 publications

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“…The discontinuous finer grain boundary M 23 C 6 precipitates are likely to contribute to improving the creep strength to some extent. [17,18] Nevertheless, this contribution could be only minor in the overall creep strength enhancement of the material, since the steady creep rate is controlled mainly by the deformation within the grains. [19] A prominent microstructural feature playing a key role in determining excellent creep properties of the material is the population of intragranular nanosized particles including the nitrogen-rich carbonitrides and Cu precipitates.…”

Section: Resultsmentioning

confidence: 98%

Improved Creep Behavior of a High Nitrogen Nb-Stabilized 15Cr-15Ni Austenitic Stainless Steel Strengthened by Multiple Nanoprecipitates

Jung

Suh

2011

Metall Mater Trans A

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Austenitic stainless steels are expected to be a major material for boiler tubes and steam turbines in future ultra-supercritical (USC) fossil power plants. It is of great interest to maximize the creep strength of the materials without increasing the cost. Precipitation strengthening was found to be the best and cheapest way for increasing the creep strength of such steels. This study is concerned with improving creep properties of a high nitrogen Nb-stabilized 15Cr-15Ni austenitic alloy through introducing a high number of nanosized particles into the austenitic matrix. The addition of around 4 wt pct Mn and 0.236 wt pct N into the 15Cr-15Ni-0.46Si-0.7Nb-1.25Mo-3Cu-Al-B-C matrix in combination with a special multicycled aging-quenching heat treatment resulted in the fine dispersion of abundant quantities of thermally stable (Nb,Cr,Fe)(C,N) precipitates with sizes of 10 to 20 nm. Apart from the carbonitrides, it was found that a high number of coherent copper precipitates with size 40 to 60 nm exist in the microstructure. Results of creep tests at 973 K and 1023 K (700°C and 750°C) showed that the creep properties of the investigated steel are superior compared to that of the commercial NF709 alloy. The improved creep properties are attributed to the improved morphology and thermal stability of the carbonitrides as well as to the presence of the coherent copper precipitates inside the austenitic matrix.

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Section: Resultsmentioning

confidence: 98%

Improved Creep Behavior of a High Nitrogen Nb-Stabilized 15Cr-15Ni Austenitic Stainless Steel Strengthened by Multiple Nanoprecipitates

Jung

Suh

2011

Metall Mater Trans A

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“…3b and Fig. 5b likely increased resistance against grain boundary sliding of the steel [30,31], and therefore, also contributed to improving the creep strength to certain extent. The transformation of (Nb,Cr)N phase precipitates to Z-phase precipitates with increase Re-query Fig.…”

Section: Discussionmentioning

confidence: 97%

Creep behavior and microstructure evolution at 750°C in a new precipitation-strengthened heat-resistant austenitic stainless steel

Jung

2012

Materials Science and Engineering: A

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“…The stress controlling the dislocation velocity is reduced to an effective value obtained by subtracting the stress necessary for overcoming precipitates from the applied stress. Equation 1is then replaced by [52,53]:…”

Section: Discussionmentioning

confidence: 99%

Intermediate-Temperature Creep Deformation and Microstructural Evolution of an Equiatomic FCC-Structured CoCrFeNiMn High-Entropy Alloy

Cao

Tong

et al. 2018

Entropy

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The tensile creep behavior of an equiatomic CoCrFeNiMn high-entropy alloy was systematically investigated over an intermediate temperature range (500–600 °C) and applied stress (140–400 MPa). The alloy exhibited a stress-dependent transition from a low-stress region (LSR-region I) to a high-stress region (HSR-region II). The LSR was characterized by a stress exponent of 5 to 6 and an average activation energy of 268 kJ mol−1, whereas the HSR showed much higher corresponding values of 8.9–14 and 380 kJ mol−1. Microstructural examinations on the deformed samples revealed remarkable dynamic recrystallization at higher stress levels. Dislocation jogging and tangling configurations were frequently observed in LSR and HSR at 550 and 600 °C, respectively. Moreover, dynamic precipitates identified as M23C6 or a Cr-rich σ phase were formed along grain boundaries in HSR. The diffusion-compensated strain rate versus modulus-compensated stress data analysis implied that the creep deformation in both stress regions was dominated by stress-assisted dislocation climb controlled by lattice diffusion. Nevertheless, the abnormally high stress exponents in HSR were ascribed to the coordinative contributions of dynamic recrystallization and dynamic precipitation. Simultaneously, the barriers imposed by these precipitates and severe initial deformation were referred to so as to increase the activation energy for creep deformation.

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Grain boundary precipitation strengthening in high temperature creep of Fe15Cr25Ni alloys

Cited by 22 publications

References 6 publications

Improved Creep Behavior of a High Nitrogen Nb-Stabilized 15Cr-15Ni Austenitic Stainless Steel Strengthened by Multiple Nanoprecipitates

Improved Creep Behavior of a High Nitrogen Nb-Stabilized 15Cr-15Ni Austenitic Stainless Steel Strengthened by Multiple Nanoprecipitates

Creep behavior and microstructure evolution at 750°C in a new precipitation-strengthened heat-resistant austenitic stainless steel

Intermediate-Temperature Creep Deformation and Microstructural Evolution of an Equiatomic FCC-Structured CoCrFeNiMn High-Entropy Alloy

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