The role of boron in modifying the solidification and microstructure of nickel-base alloy U720Li

Zhao, Guangdi; Yu, Lianxu; Yang, Guoliang; Zhang, Weihong; Sun, Wei

doi:10.1016/j.jallcom.2016.05.331

Cited by 29 publications

(8 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The in situ composition analysis by EDS (Table 1) suggests that the borides are mainly composed with Mo and Cr, which is in agreement with the element distribution determined by EPMA and the previous reports [12][13][14]. The Zr-bearing particles are mainly composed with Ni and Zr, which is consistent with the previous studies [4,15]. The g phase is highly enriched in Ni and Ti, and similar results have been reported in the literature [16].…”

Section: Resultssupporting

confidence: 91%

Transformation Mechanism of (γ + γ′) and the Effect of Cooling Rate on the Final Solidification of U720Li Alloy

Zhao

Yang

Liu

et al. 2017

Acta Metall. Sin. (Engl. Lett.)

View full text Add to dashboard Cite

The transformation mechanism of (c ? c 0) was studied by analyzing the microstructure and elemental distribution of the U720Li samples heated at 1250°C and cooled at the rates in the range of 1-100°C/s. Although the (c ? c 0) is deemed to be formed by a eutectic reaction and has been called eutectic (c ? c 0), it was found in the present study that the (c ? c 0) precipitation begins with a peritectic reaction of (L ? c) ? c 0 , and develops by the eutectic reaction of L ? (c ? c 0). The energy for the c 0 nucleation is low because the interfacial energy for the c/c 0 interface is about one-tenth of the solid/liquid interface, and hence, the nucleation rate is high and the fine structure of (c ? c 0) is formed at the initial precipitation stage. The c and c 0 in (c ? c 0) tend to grow into a lamellar structure because it is difficult for them to nucleate directly from the residual liquids, and hence, the c 0 precipitates naturally tend to grow divergently direction of the regions rich in Al and Ti, forming a fan-like structure of the (c ? c 0). As a result, the c 0 precipitates will coarsen finally because the space between them is enlarged. The solidification of the final residual liquids is a diffusion dependent process. When cooled at a higher rate, a higher degree of super cooling is reached and finally the solidification is finished by the pseudoeutectic reaction of L ? (c ? boride) and L ? (c ? g), which can absorb Zr and B. When cooled at a rate low enough, most of the residual liquids are consumed by the (c ? c 0) growth due to the sufficient diffusion, and the boride and Zrbearing phase are precipitated at a quasi-equilibrium state. Under this condition, Ti is depleted at the (c ? c 0) growth front. However, the g-Ni 3 Ti phase is formed there occasionally due to the boride precipitation, because the compositions of the two phases are complementary.

show abstract

Section: Resultssupporting

confidence: 91%

Transformation Mechanism of (γ + γ′) and the Effect of Cooling Rate on the Final Solidification of U720Li Alloy

Zhao

Yang

Liu

et al. 2017

Acta Metall. Sin. (Engl. Lett.)

View full text Add to dashboard Cite

show abstract

“…Understanding the microstructure evolution and elemental segregation before the nonequilibrium phases formation is critical to study the influencing mechanism of Zr on these phases [5] . Thus, a high temperature quenching test was performed.…”

Section: Methodsmentioning

confidence: 99%

“…Besides, they also have significant effects on solidification microstructures. For example, C addition obviously reduces eutectic (γ+γ′) formation [23][24][25] , while certain amounts of B/Zr addition significantly increases its formation [5,22,[26][27][28] . From the perspective of cost and applicability, reasonable controlling addition of these minor elements should be the most suitable method to reduce formation of the nonequilibrium phases.…”

Section: Effect Of Zr On Solidification and Microstructure Of A Ni-based Superalloy With High Al And Ti Contentsmentioning

confidence: 99%

“…Many investigations have discussed about how the C and B affect solidification microstructures of Ni-based superalloys [23][24][25][27][28] . Recently, the influencing mechanisms of C and B on the eutectic (γ+γ′) and η precipitation in U720Li alloy were revealed on the base of previous studies [5,29] . While, only a few researchers have discussed about how Zr affects precipitation of the nonequilibrium phases in Ni-based superalloys, and the mechanism is still controversial.…”

Section: Effect Of Zr On Solidification and Microstructure Of A Ni-based Superalloy With High Al And Ti Contentsmentioning

confidence: 99%

“…To satisfy the demand that aero-engines continue to develop, the total amount of γ′ (the main strengthening phase) forming elements Al and Ti in advanced alloys has reached 7.5wt.% [3,4] . However, the more the addition of (Al+Ti), the easier to form nonequilibrium eutectic (γ+γ′) and η phase at the final solidification stage [5,6] . U720Li is a relatively advanced Ni-based superalloy containing high (Al+Ti) content [7,8] .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Effect of Zr on solidification and microstructure of a Ni-based superalloy with high Al and Ti contents

et al. 2022

View full text Add to dashboard Cite

Ni-based wrought superalloys are key materials for aero-engines turbine disks, chiefly owing to their superior corrosion, fatigue and creep resistance at elevated temperatures [1,2] . To satisfy the demand that aero-engines continue to develop, the total amount of γ′ (the main strengthening phase) forming elements Al and Ti in advanced alloys has reached 7.5wt.% [3,4] . However, the more the addition of (Al+Ti), the easier to form nonequilibrium eutectic (γ+γ′) and η phase at the final solidification stage [5,6] . U720Li is a relatively advanced Ni-based superalloy containing high (Al+Ti) content [7,8] . It was found that the eutectic (γ+γ′) and η phases were easy to become source of crack initiation sites during hot deformation of U720Li ingots [9] . Thus, these two phases must be eliminated by high temperature

show abstract

Effect of tempering temperature on microstructure and properties of aluminium‐bearing high boron high speed steel

Zhang

et al. 2020

Materialwissenschaft Werkst

View full text Add to dashboard Cite

Heat treatment is of great significance to the performance improvement of high speed steel. Via heat treatment, the microstructure of high speed steel can be improved, thus greatly improving the material performance. The effect of tempering temperature on the microstructure of aluminium‐bearing high boron high speed steel (AB‐HSS) was investigated by optical microscope (OM), scanning electron microscope (SEM) and x‐ray diffraction (XRD). The hardness and wear resistance of the alloy at different tempering temperatures were tested by Rockwell hardness tester, micro‐hardness tester and wear tester. The experimental results indicate that the tempering microstructure of aluminium‐bearing high boron high speed steel consists of α‐Fe, M2B and a few of M23(C, B)6. Tempering temperature could greatly affect the wear resistance of materials. With the increase of tempering temperature, the wear resistance of aluminium‐bearing high boron high speed steel firstly increase and then decrease. The alloy tempered at 450 °C has the best wear resistance and minimum wear weight loss. This study provides a reference for the formulation of heat treatment process of aluminium‐bearing high boron high speed steel.

show abstract

The role of boron in modifying the solidification and microstructure of nickel-base alloy U720Li

Cited by 29 publications

References 33 publications

Transformation Mechanism of (γ + γ′) and the Effect of Cooling Rate on the Final Solidification of U720Li Alloy

Transformation Mechanism of (γ + γ′) and the Effect of Cooling Rate on the Final Solidification of U720Li Alloy

Effect of Zr on solidification and microstructure of a Ni-based superalloy with high Al and Ti contents

Effect of tempering temperature on microstructure and properties of aluminium‐bearing high boron high speed steel

Contact Info

Product

Resources

About