Influence of withdrawal rate on last stage solidification path of a Mo-rich Ni3Al based single crystal superalloy

Ai, Cheng; Zhao, Xinbao; Liu, Lei; Zhang, Heng; Ru, Yi; Pei, Yanling; Zhou, Jian; Li, Shusuo; Gong, Shengkai

doi:10.1016/j.jallcom.2014.11.048

Cited by 14 publications

(5 citation statements)

References 37 publications

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“…When a stable temperature gradient was established at the solid-liquid interface, in order to maintain the continuity of the SX growth, two sets of ceramic mould shells full of melt were removed from the heating zone to the cooling zone of the furnace with the withdrawal rates of 3 mm/min and 5 mm/min, respectively. The withdrawal rate between 3 mm/min and 5 mm/min has commonly been used in the directional solidification process of turbine blade industrial production, as well as previous studies [20,26,27,29,[31][32][33][34][35][36][37]. When the withdrawal rate was lower than 3 mm/min, it affected production efficiency of turbine blades, but when it was higher than 5 mm/min, the height of the blade's 'mushy zone' was increased, and the tendency towards crystal defect formation, such as sliver grains and stray grains [26], was promoted.…”

Section: Methodsmentioning

confidence: 99%

“…It was reported that primary dendrite arm spacing increased with increases in the withdrawal rate. Ai et al [31] investigated the solidification behaviours of a Mo-rich Ni3Al-based SX superalloy at different withdrawal rates. It was concluded that, because of solid back diffusion during solidification, the volume fraction of inter-dendritic precipitation initially increased and then decreased with an increased withdrawal rate.…”

Section: Introductionmentioning

confidence: 99%

“…However, in these studies, the effects of withdrawal rate on microstructural morphologies of SX nickel-based superalloys were based on simplified geometrical castings, such as rods and blade models [28][29][30][31][32][33][34][35][36]. Compared with simplified geometrical castings, the structures of hollow blades for aero-engines are more complex, which leads to varieties of radiation heat transfers in different positions of the turbine blades during the directional solidification process.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Withdrawal Rate on Solidification Microstructures of DD9 Single Crystal Turbine Blade

et al. 2023

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Single crystal superalloys are widely used in the manufacturing of turbine blades for aero-engines due to their superior performance at high temperatures. The directional solidification process is a key technology for producing single crystal turbine blades with excellent properties. In the directional solidification process, withdrawal rate is one of the critical parameters for microstructure formation and will ultimately determine the blade’s properties. In this paper, the as-cast microstructures in the typical sections of a DD9 single crystal (SX) superalloy turbine blade were investigated with 3 mm/min and 5 mm/min withdrawal rates during the directional solidification process. With increased withdrawal rate, the dendrite morphologies tended to become more refined, and the secondary dendritic arms tended to be highly developed. The dendrite in the blade aerofoil section was more refined than that in the tenon section, given the same withdrawal rate. Additionally, with increasing withdrawal rates, the size and dispersity of the γ′ precipitates in the inter-dendritic (ID) regions and dendritic core (DC) tended to decrease; furthermore, the size distributions of the γ′ precipitates followed a normal distribution law. Compared with the ID regions, an almost 62% reduction in the average γ′ sizes was measured in the DC. Meanwhile, given the same withdrawal rate, at the blade’s leading edge closest to the heater, the γ′ sizes in the aerofoil section (AS) were more refined than those in the tenon section (TS). As compared with the decreasing cross-sectional areas, the increased withdrawal rates clearly brought down the γ′ sizes. The sizes of the γ–γ′ eutectics decreased with increasing withdrawal rates, with the γ–γ′ eutectics showing both lamellar and rosette shapes.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Withdrawal Rate on Solidification Microstructures of DD9 Single Crystal Turbine Blade

et al. 2023

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“…A multi-platform software program called Jmatpro was used to investigate the phase equilibrium of the 1# samples (Ai et al, 2015(Ai et al, , 2017Rai et al, 2017). It can be seen that Al 7 Cu 2 Mg with low melting point (approximately 510°C) is the main liquid phases in the molten pool (Figure 2c).…”

Section: The Cracks Of Slmed 7050 Alloymentioning

confidence: 99%

Effect of Si content on the cracking behavior of selective laser melted Al7050

Zhu

Zeng

et al. 2019

RPJ

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Purpose It is a crucial issue to eliminate cracks for selective laser melting (SLM) 7xxx series aluminum alloy. This paper aims to study the effect of silicon content on the cracking behavior and the mechanism of eliminating crack of SLMed Al7050 alloy. Design/methodology/approach Six different silicon contents were added to the Al7050 powder. The crack density and crack count measuring from optical micrographs were utilized to judge the cracking susceptibility. The low melting phases analyzing from Jmatpro and the microstructure observing by EPMA and SEM were used to discuss the mechanism of eliminating the crack. Findings The cracking susceptibility of SLMed Al7050 alloy decreases with the increase of adding silicon content. When adding silicon, two new low-melting phases appeared: Mg2Si and Al5Cu2Mg8Si6. These low-melting phases offer much liquid feeding along the grain boundary and decrease the cracking susceptibility. Moreover, the grains are obviously refined after adding silicon. The fine grain can increase the total surface area of the grain boundary, which can reinforce the matrix and decrease the cracking susceptibility. High silicon content results in more low-melting phases and fine grains, which decreases the cracking susceptibility. Originality/value The investigation results can help to obtain crack-free SLMed Al7050 parts and deep knowledge on eliminating cracking mechanism of high-strength aluminum alloy fabricated by SLM.

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“…Thixoforming is a near-net-shape manufacturing process that is performed at temperatures between the solidus and the liquidus [1][2][3], with different recrystallization behavior from conventional process [4][5][6][7][8]. The most distinct characteristic of thixoformed microstructure is the co-existence of liquid and solid during processing (since this occurs at semi-solid temperatures), and the formation of a primary phase with near-spherical grain morphology [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Alloy development and reheating process exploration of Al–Si casting alloys with globular grains for thixoforming

Wang

Zhang²,

Phillion

et al. 2016

J. Mater. Res.

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A novel two-stage reheating process with new alloy design has been developed to improve the microstructure morphology of semi-solid Al-Si casting aluminum alloy for thixoforming. The process consists of first reheating the material to the liquidus temperature, holding for 5 minutes, and then lowering to the predetermined two-stage reheating temperature between 843 -863 K and holding for 10 minutes. The experimentally-obtained grain diameter, roundness, and the amount of liquid trapped within the solid phase were characterized, along with the microstructure obtained using the traditional feedstock reheating process. The Wilcox test (with α=0.05) was then applied to statistically analyze the measured differences in the microstructures obtained using the two different processing routes. It was found that a refined near-spherical structure with uniform globule size, higher sphericity, lower coarsening rate constant, and less entrapped liquid was obtained via the new two-stage reheating process in comparison with the microstructure obtained using the traditional feedstock reheating process.

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Influence of withdrawal rate on last stage solidification path of a Mo-rich Ni3Al based single crystal superalloy

Cited by 14 publications

References 37 publications

Effect of Withdrawal Rate on Solidification Microstructures of DD9 Single Crystal Turbine Blade

Effect of Withdrawal Rate on Solidification Microstructures of DD9 Single Crystal Turbine Blade

Effect of Si content on the cracking behavior of selective laser melted Al7050

Alloy development and reheating process exploration of Al–Si casting alloys with globular grains for thixoforming

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