GCP and TCP Phases Presented in Nickel-base Superalloys

Belán, Juraj

doi:10.1016/j.matpr.2016.03.024

Cited by 58 publications

(33 citation statements)

References 11 publications

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“…The main secondary phases in the alloy 686 weldment are identified as r (tetragonal), P (orthorhombic) and l (rhombohedral) phases. The P phase occurrs in the temperature range of 950-1050°C [22] whereas r phase is formed in the range of 540-980°C [8] and l phase evolves in the temperature range of 540-870°C [23]. In the present investigation, the chemical composition of P and l phases closely matches those reported in the existing literature [8].…”

Section: Tensile Testsupporting

confidence: 88%

Effect of post-weld heat treatment on the microstructure and tensile properties of electron-beam-welded 21st century nickel-based super alloy 686

et al. 2019

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This work examines the influence of post-weld heat treatment (PWHT) on the fusion zone microstructure, and mechanical properties of electron beam (EB)-welded alloy 686. Comparative studies have been made on weld microstructure and tensile properties of the weldments both in as-welded and post-welded heat-treated conditions. PWHT consists of direct aging (DA/480°C for 3 h) and solution treatment (ST, 980°C for 1 h) followed by ageing and finally, homogenizing treatment (HT, 1200°C for 1 h) followed by DA and ST. The secondary topologically closed packed (TCP) phases formation, their distribution and microsegregation characteristics are studied with the aid of scanning electron microscope (SEM) analysis. Energy-dispersive X-ray spectroscopy (EDS) is also performed to estimate the microsegregation of alloying elements in the dendritic core and interdendritic regions of the weldments. The result shows that there is no significant change in the microstructure of DA and solution-treated sample as compared to the as-welded sample. The microstructure of HT sample was entirely different from those of as-welded and other HT samples. The SEM/EDS analysis illustrates the presence of secondary TCP phases (r, P and l) in the as-weld, DA and ST condition, whereas HT weldments did not show the presence of TCP phases. Tensile test results show higher tensile strength in ST condition whereas homogenization samples show higher ductility compared with others.

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Section: Tensile Testsupporting

confidence: 88%

Effect of post-weld heat treatment on the microstructure and tensile properties of electron-beam-welded 21st century nickel-based super alloy 686

et al. 2019

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“…4c). These precipitates were mainly chromium-rich M 23 C 6 and molybdenum-rich M 6 C according to the literature [11][12][13][14].…”

Section: Advances In Engineering Research (Aer) Volume 102mentioning

confidence: 56%

Effects of Hot Isostatic Pressing on Microstructure and Mechanical Properties of Hastelloy X Samples Produced by Selective Laser Melting

Li¹,

Qi²,

Hou³

et al. 2017

Proceedings of the Second International Conference on Mechanics, Materials and Structural Engineering (ICMMSE 2017)

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Abstract. Hot isostatic pressing (HIP) with two different temperatures of 1100○ C/160MPa/2h and 1175 ○ C/160 MPa/2 h was performed on Hastelloy X samples produced by selective laser melting (SLM) was performed. The effect of hot isostatic pressing on defects, microstructures and mechanical properties of SLM fabricated Hastelloy X samples were investigated. It showed that cracks and micro-pores on within SLM-fabricated samples were gradually eliminated with the increase of HIP temperatures, increased A in which nearly fully dense part can be achieved at hot isostatic pressing of 1175 ○ C /160 MPa/2 h. The microstructure evolution rule as follows: cellular crystal in both horizon and vertical directions, no precipitates (as-deposited) → equiaxed crystal with size of 10-50 μm in horizon direction and columnar crystal with size of 200μm in vertical direction, chain-like precipitates distributed at grain boundaries (1100 ○ C/160 MPa/2 h HIP processed) → equiaxed crystal with size of 150 μm in both horizon and vertical directions, plate-like precipitates distributed at grain boundaries with size triple increased (1175 ○ C/160 MPa/2 h HIP processed). Ductile fracture occurred in both SLM deposited and HIP processed samples during room temperature tensile tests, while all tested samples behaved higher mechanical properties than traditional wrought parts. The room temperature tensile properties of the as-deposited and the two HIP processed samples all reached the standard for wrought Hastelloy X. Moreover, the ductility of HIP processed samples enhanced and tensile properties decreased compared with SLM deposited samples.

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“…According to literature, d precipitates can have an effect on stress rupture, but when they get coarser and in higher amounts they degrade mechanical properties. 15,28 Regarding yield strength and elongation, no effective trends are appreciable. Conversely to the case of tensile strength, yielding appears not to be affected by stabilization time and temperature.…”

Section: Discussionmentioning

confidence: 98%

“…In the CU5CuMC alloy, adding niobium together with a stabilization thermal treatment, overcomes the sensitization, bringing about the formation of stable Nb carbides. [13][14][15] However, detailed studies of precipitation in these alloys are rare.…”

Section: Introductionmentioning

confidence: 99%

“…As is well known, large precipitates are incoherent, and the strengthening effect is limited but this can help to obtain the desired mechanical properties. Some evidence 15 also suggests that the shape of the precipitate can improve the yield strength, in particular, acicular long and thin precipitates seem to confer a greater strengthening effect than globular ones.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Response of Ni-Based CU5MCuC Alloy to Different Stabilization Thermal Treatments

2020

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The Ni–Fe–Cr system is the basis of a series of commercial alloys featuring chemical–physical characteristics that allow them to be used in a variety of fields where excellent resistance to aggressive environments is required. In this scenario, the CU5MCuC alloy, the foundry counterpart of Alloy 825, is proving successful in the petrochemical field thanks to its good corrosion resistance in acidic and highly oxidizing environments. Intergranular corrosion resistance, critical for this material, is ensured by the stabilization treatment that allows precipitation of Nb carbides. Strengthening of this alloy takes place only via a solid solution. Therefore, its mechanical properties depend on the solution annealing treatment: often this treatment alone does not make it possible to reach the UTS imposed by the ASTM-A494 standard. In this work, the possibility of using stabilization treatment to increase mechanical strength as well was considered. Treatments, with different combinations of time and temperature, were carried out in order to modify the material’s microstructure. After the thermal treatments, microstructural analyses, mechanical tests and (pitting and intergranular) corrosion and resistance tests were carried out to identify optimal treatment parameters in order to promote the evolution of microstructural constituents capable of improving mechanical strength without decreasing corrosion resistance. The treatment that achieves the best compromise between mechanical properties and corrosion resistance is stabilization at 970 °C for 4 h.

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GCP and TCP Phases Presented in Nickel-base Superalloys

Cited by 58 publications

References 11 publications

Effect of post-weld heat treatment on the microstructure and tensile properties of electron-beam-welded 21st century nickel-based super alloy 686

Effect of post-weld heat treatment on the microstructure and tensile properties of electron-beam-welded 21st century nickel-based super alloy 686

Effects of Hot Isostatic Pressing on Microstructure and Mechanical Properties of Hastelloy X Samples Produced by Selective Laser Melting

Mechanical Response of Ni-Based CU5MCuC Alloy to Different Stabilization Thermal Treatments

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