Dependence of Creep Performance and Microstructure Evolution on Solution Cooling Rate in a Polycrystalline Superalloy

Xu, Chao; Liu, Feng; Huang, Lan; Jiang, Liang

doi:10.3390/met8010004

Cited by 7 publications

(3 citation statements)

References 21 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…При этом следует избегать значительного роста γ-зерен. По данным работ [7 -9], сохранение мелкозернистой структуры (d γ =10 -20 мкм) особенно важно для ступичной части дисков ГТД, от которой в процессе эксплуатации требуются одновременно высокая прочность, ударная вязкость, пластичность, сопротивление усталостному разрушению и термоциклическим нагрузкам [4,5,10].…”

Section: Introductionunclassified

Long-term strength and creep resistance of a polycrystalline Re-containing nickel-based superalloy

et al. 2021

View full text Add to dashboard Cite

The work was devoted to the study of the long-term strength and creep resistance of the recently developed heat resistant nickel-based superalloy SDZhS-15 intended for manufacturing of discs for gas turbine engines. The as-cast alloy was subjected to homogenization heat treatment, hot forging at subsolvus temperatures with intermediate annealing, solution treatment at various temperatures and aging or only to aging. A predominantly fine-grained structure was obtained in the workpieces after forging. It was revealed that solution treatment at T > T s − 50, where T s is the solvus temperature of the γ'-phase, led to a decrease in the volume fraction of the primary γ'-phase and an increase in the volume fraction of the γ' precipitates together with a significant growth of γ grains (up to d > 50 μm). Solution treatment at Т = T s − 50 allowed maintaining a relatively finegrained structure (d γ =10 -20 μm) and ensured the precipitation of the secondary γ'-phase with a size of about 0.1 μm upon cooling in air. Three microstructure conditions were obtained, for which long-term strength and creep resistance tests were performed in the range of temperatures 650 -850°C and stresses 400 -1200 MPa. The highest values of the long-term strength were achieved for a relatively fine-grained condition obtained after solution treatment at T s − 50 and aging. To evaluate the service life of the superalloy, the methodology based on the calculation of the Larson-Miller parameter was used. It was shown that the long-term strength (creep resistance) of the SDZhS-15 alloy in the optimal condition was higher as compared to the industrial disc nickel-based superalloys EP741NP and Udimet 720. Microstructure examination of the creep tested samples did not result in significant microstructure changes and especially in the formation of topologically close-packed phases. After creep tests, microcracks were observed along the grain / interphase boundaries, which apparently resulted from the development of boundary diffusion and sliding.

show abstract

Section: Introductionunclassified

Long-term strength and creep resistance of a polycrystalline Re-containing nickel-based superalloy

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In general, the technological process of powder metallurgy consists of four main stages: production of powders, mixing of powders, compaction (pressing, forming) and consequent sintering [12][13][14][15][16][17][18][19]. Often the way of powder compaction in preforms under all equal conditions predetermines the properties of the final product and takes a critical role in the formation of the internal structure (homogeneity, absence of pores, cracks) [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

A Cold-Pressing Method Combining Axial and Shear Flow of Powder Compaction to Produce High-Density Iron Parts

et al. 2019

View full text Add to dashboard Cite

Highly performance methods for cold pressing (cold die forging) of preforms from iron powder with subsequent heat treatment and producing ready parts made of powder are described in the paper. These methods allow fabricating parts with smooth surfaces and improved mechanical characteristics—porosity, tensile strength. Application of the traditional design set-up with a single-axial loading is restricted to high stresses in the dies to deform the preforms that lead to cracks formation. New powder compaction schemes by applying active friction forces (shear-enhanced compaction) make it possible to unload dies and produce high-quality parts by cold pressing. The scheme allows moving the die in the direction of the material flow with a velocity that exceeds the material flow velocity.

show abstract

“…Nickel-based superalloy blades [1][2][3][4][5][6][7], which possess excellent high-temperature creep resistance, have been proven to be successful in aero-engine and industrial gas turbines (IGTs). To improve the high-temperature performance of superalloy blades, the columnar polycrystal and single crystal structures are favored, while the directional solidification (DS) techniques have become the choice for production over the past few decades.…”

Section: Introductionmentioning

confidence: 99%

Multiscale Modeling and Simulation of Directional Solidification Process of Ni-Based Superalloy Turbine Blade Casting

Yang

Zhang

et al. 2018

Metals

View full text Add to dashboard Cite

Ni-based superalloy turbine blades have become indispensable structural parts in modern gas engines. An understanding of the solidification behavior and microstructure formation in directional solidified turbine blades is necessary for improving their high-temperature performance. The multiscale simulation model was developed to simulate the directional solidification process of superalloy turbine blades. The 3D cellular automaton-finite difference (CA-FD) method was used to calculate heat transfer and grain growth on the macroscopic scale, while the phase-field method was developed to simulate dendrite growth on the microscopic scale. Firstly, the evolution of temperature field of an aero-engine blade and a large industrial gas turbine blade was studied under high-rate solidification (HRS) and liquid-metal cooling (LMC) solidification processes. The varying withdrawal velocity was applied to change the curved mushy zone to a flat shape. Secondly, the grain growth in the aero-engine blade was simulated, and the grain structures in the starter block part and the spiral selector part in the HRS process were compared with those in the LMC process. The simulated grain structures were generally in agreement with experimental results. Finally, the dendrite growth in the typical HRS and LMC solidification process was investigated and the simulation results were compared with the experimental results in terms of dendrite morphology and primary dendritic spacing.

show abstract

Dependence of Creep Performance and Microstructure Evolution on Solution Cooling Rate in a Polycrystalline Superalloy

Cited by 7 publications

References 21 publications

Long-term strength and creep resistance of a polycrystalline Re-containing nickel-based superalloy

Long-term strength and creep resistance of a polycrystalline Re-containing nickel-based superalloy

A Cold-Pressing Method Combining Axial and Shear Flow of Powder Compaction to Produce High-Density Iron Parts

Multiscale Modeling and Simulation of Directional Solidification Process of Ni-Based Superalloy Turbine Blade Casting

Contact Info

Product

Resources

About