Precipitation behavior of grain boundary M23C6 and its effect on tensile properties of Ni–Cr–W based superalloy

Hu, Rui; Bai, Guanghai; Li, Jinshan; Zhang, Jingqing; Zhang, Tiebang; Fu, Hengzhi

doi:10.1016/j.msea.2012.03.092

Cited by 143 publications

(32 citation statements)

References 27 publications

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“…Discontinuous coarsening of M 23 C 6 has been extensively reported to cause GB weakening and creep failure in Haynes 230 and similar alloy systems (Refs. [52][53][54]. Interconnected M 23 C 6 morphology are also reported to lower the ductility and tensile strength in similar Ni-Cr-W alloys causing fracture (Ref.…”

Section: A B a Bmentioning

confidence: 97%

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Stress Relief Cracking Susceptibility in High-Temperature Alloys

Kant¹

2019

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The stress relief cracking (SRC) susceptibility of a range of austenitic and ferritic alloys was tested using Gleeble ® based test procedures. The tests were developed to study the effect of postweld heat treatment (PWHT) temperature and cold working on the SRC susceptibility. Six susceptibility parameters were identified from the test results (ductility, percentage stress relaxed, hardness increase at fracture, failure time, fracture mode, and extent/type of secondary cracks below the fracture). The susceptibility parameters were integrated with concepts of Risk Priority Number (a prioritization tool in 6-Sigma) to develop an SRC susceptibility index. Sensitivity analysis of the methodology was done to ensure its robustness. The ferritic alloys generally showed the highest SRC susceptibility at a PWHT temperature of 600C, while the austenitic alloys were generally most susceptible at 800C. Using the susceptibility index, the SRC tendency of all the alloys was divided into three regions (highly susceptible, moderately susceptible, and resistant). The newly proposed test procedure and SRC susceptibility index provide a robust approach for studying and ranking the SRC susceptibility of engineering alloys. Posttest microstructural characterization of the SRC samples provided insight into the cracking mechanisms. FEBRUARY 2019 / WELDING JOURNAL 29-s https://doi.org/10.29391/2019.98.003

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Section: A B a Bmentioning

confidence: 97%

“…Interconnected M 23 C 6 morphology are also reported to lower the ductility and tensile strength in similar Ni-Cr-W alloys causing fracture (Ref. 54). Even though no apparent PFZ was observed, the GB coarsening of Cr-rich phase can locally deplete the matrix in both Cr and W, thereby forming a locally softened region.…”

Section: A B a Bmentioning

confidence: 97%

Stress Relief Cracking Susceptibility in High-Temperature Alloys

Kant¹

2019

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“…However, the mechanical properties of alloy 690 are noticeably inferior to those of alloy 600 [4] while its chemical properties are significantly improved. The mechanical properties of Ni-based alloys are dependent on the morphology and distribution of precipitates in the matrix [5]. Generally, under the conditions of heat treatment or during high-temperature service, M 23 C 6 , as a typical carbide commonly precipitates at the grain boundary in alloy 690 [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Effect of a heat treatment on the precipitation behavior and tensile properties of alloy 690 steam generator tubes

Lee

Suh

Han

et al. 2016

Journal of Nuclear Materials

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The intergranular carbide precipitation behavior and its effect on the tensile properties were investigated in alloy 690. The precipitation of intergranular carbides, identified as Crrich M 23 C 6 , was retarded on the low-angle grain boundaries and the coincidence-site lattice boundaries. The M 23 C 6 carbides have a cube-cube orientation relationship with the matrix. The ultimate tensile strength, yield strength, and elongation of the solution annealed alloy 690 are 648.2±8.2 MPa, 242.8±10.5 MPa and 44.9±2.3 %, respectively. The ultimate tensile strength and the yield strength increased to 764.8±7.8 MPa and 364.8±10.2 MPa until the aging time reached 16 hours. This increase is ascribed to the M 23 C 6 carbide acting as reinforcements. However, when the aging time exceed 16 hours, these properties gradually decreased with increasing aging time. The decrease in ultimate tensile strength, yield strength, and elongation were mainly caused by the intergranular cracking due to the low bond strength between the carbide and the matrix.

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“…For the case of Hastelloy N studied in this work, it is a representative Ni-based solid solution strengthened alloy invented by Oak Ridge National Laboratory (ORNL) specifically for use in molten fluoride nuclear reactor system in the 1960s [8]. For the constitution of Ni-Mo-Cr alloys, researchers have reached a consensus that they were basically composed of Ni-based solid solution and precipitates [9][10][11], but what type of precipitates was still subjected to debate. There are currently two viewpoints.…”

Section: Introductionmentioning

confidence: 99%