Examination of Ni-based superalloy/intermetallic diffusion couples containing multiphase regions

McGregor, Megan; Hancock, Matthew; Pallett, Lloyd; Clegg, W.J.

doi:10.1016/j.intermet.2019.106559

Cited by 11 publications

(2 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A similar observation has been reported for the Ni-Al-Ta system, where the (Ni, Al) 2 Ta Laves_C14 phase transforms to the Ni 2 TaAl Heusler phase with L2 1 structure due to interdiffusion. [38] From the experimentally determined compositions for the Laves_C14 and Fe 2 SiTi phases, it is evident that there is a dissolution of Nb into these phases, possibly into the Ti sublattice due to their chemical similarities. It can also be observed that the measured composition of Fe is higher in the Fe 2 SiTi phase.…”

Section: As-cast Designed and Conventional Hsla-115 Steelsmentioning

confidence: 99%

Thermodynamic Investigation of New High-Strength Low-Alloy Steels with Heusler Phase Strengthening for Welding and Additive Manufacturing: High-Throughput CALPHAD Calculations and Key Experiments for Database Verification

Wang

Sridar

2020

J. Phase Equilib. Diffus.

View full text Add to dashboard Cite

High-strength low-alloy (HSLA) steels often comprise of Cu clusters and M 2 C (M: Mo, Cr) carbides as strengthening particles. In this work, three new HSLA steels with alternative strengthening phases, Fe 2 SiTi and Ni 3 Ti, are investigated by using HSLA-115 steel as the reference. To evaluate the weldability for potential fabrication using casting, welding, and additive manufacturing, freezing ranges are studied using differential thermal analysis (DTA), and CALPHAD (Calculation of Phase Diagrams) approach under equilibrium and nonequilibrium conditions. While the cooling signals in the DTA analysis are not pronounced enough for thermal analysis, the trend of freezing range change based on the nonequilibrium and equilibrium calculations are consistent with the heating signals. High-throughput calculations are performed to deduce the effect of variation of each alloying element on the freezing range. Moreover, the experimental and calculated phase fractions and compositions of the as-cast and heat-treated alloys were compared. Though CALPHAD model-prediction can provide valuable insights into the phase stability of these new alloys, there is a remarkable difference regarding phase fraction and composition of individual phases. Therefore, this study indicates that the application of the CALPHAD approach in new alloy discovery requires a careful model-validation and database calibration.Keywords CALPHAD Á Heusler phase Á HSLA steels Á thermal analysis Á thermodynamics This article is an invited paper selected from presentations at ''PSDK XIV: Phase Stability and Diffusion Kinetics-Gibbs: Phase Equilibria, Diffusion and Materials Design'' held during MS&T'19, September 29-October 3, 2019, in Portland, Oregon. The special sessions were dedicated to honor Dr. Patrice Turchi, recipient of the ASM International 2019 J. Willard Gibbs Phase Equilibria Award ''for outstanding and pioneering contributions in the application of first-principles, quantum-mechanical calculations to the modeling of phase equilibria and thermodynamic behavior of alloys.'' It has been expanded from its original presentation.

show abstract

Section: As-cast Designed and Conventional Hsla-115 Steelsmentioning

confidence: 99%

Thermodynamic Investigation of New High-Strength Low-Alloy Steels with Heusler Phase Strengthening for Welding and Additive Manufacturing: High-Throughput CALPHAD Calculations and Key Experiments for Database Verification

Wang

Sridar

2020

J. Phase Equilib. Diffus.

View full text Add to dashboard Cite

show abstract

“…c 0 / b ? Laves phase in CMSX-4/NiAlTa systems [40] the effective phase model has been used. DMJs in many practical applications consist of different classes of alloys and in such cases DICTRA simulation is a bit tricky.…”

Section: Introductionmentioning

confidence: 99%

Interdiffusion Studies in Alloy 617 and 10Cr Steel Joints Using Diffusion Couple Approach and Simulations

Haribabu,

Sudha,

Ganesh

et al. 2024

J. Phase Equilib. Diffus.

View full text Add to dashboard Cite

In the steam turbine circuit of advanced ultra supercritical power plants dissimilar joints of alloy 617 and 10Cr steel are unavoidable due to economic reasons. In these joints diffusional interaction causing change in microstructure is identified as possible reason for failure during service. To investigate the interdiffusion driven structural changes, alloy 617/10Cr steel diffusion couples were fabricated. To achieve good metallurgical bond between Fe- and Ni-based alloys and to study diffusional transformations under accelerated conditions, diffusion couples were prepared by annealing in the temperature range of 1000-1100 °C for 3-8 h. For all conditions heat treatment interaction zones were wider in alloy 617 (150-200 μm at 1050 °C, 8 h) than in 10Cr steel (15-16 μm at 1050 °C, 8 h) and the phase stability at the interface was studied using electron microprobe and x-ray diffraction. Average effective interdiffusion coefficients were calculated using Dayananda’s approach. While the diffusivities of substitutional solutes were similar in alloy 617 (0.31-0.42 × 10−15 m2/s at 1050 °C), they differed in 10Cr steel in the following sequence: $$\tilde{D}_{{{\text{Cr}}}}$$ D ~ Cr > $$\tilde{D}_{{{\text{Fe}}}}$$ D ~ Fe ≈$$\tilde{D}_{{{\text{Ni}}}}$$ D ~ Ni > $$\tilde{D}_{{{\text{Co}}}}.$$ D ~ Co . Further, multicomponent interdiffusion profiles were predicted using homogenization model in DICTRA and an integrated approach combining DICTRA with Thermo-Calc helped in understanding the experimental observations on the interface microstructure.

show abstract

Laser-based directed energy deposition and characterisation of cBN-reinforced NiAl-based coatings

Müller,

Gerdt,

Schrüfer

et al. 2024

Int J Adv Manuf Technol

View full text Add to dashboard Cite

Within this study, the alloy NiAl–2.5Ta–7.5Cr is investigated as a new matrix material for cBN-reinforced abrasive turbine blade tip coatings as currently used NiCoCrAlY matrix alloys suffer from insufficient strength at the high operating temperatures. Laser-based directed energy deposition with blown powder was applied to produce cBN reinforced NiAl-based coatings on monocrystalline CMSX-4 substrates. For this, powdery titanium-coated cBN and NiAl–2.5Ta–7.5Cr material were co-injected into the process zone to achieve an in situ formation of a NiAl–2.5Ta–7.5Cr/cBN composite. In order to overcome challenges such as cracking susceptibility, inductive preheating of the substrate up to 800 °C was used. Optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, as well as electron backscatter diffraction were applied to analyse the fabricated samples’ microstructure. Additionally, the mechanical properties were evaluated by means of microhardness mappings. This work demonstrates the feasibility of in situ forming a metal matrix composite with a homogeneous distribution of cBN particles. The results show the beneficial effect of high-temperature preheating on the crack formation. However, the study also reveals challenges such as cracking induced by the injected cBN particles as well as severe intermixing of substrate and coating, which yields spatially resolved deviations in the chemical composition and resulting variations in microstructure and hardness. Graphical abstract

show abstract

Examination of Ni-based superalloy/intermetallic diffusion couples containing multiphase regions

Cited by 11 publications

References 35 publications

Thermodynamic Investigation of New High-Strength Low-Alloy Steels with Heusler Phase Strengthening for Welding and Additive Manufacturing: High-Throughput CALPHAD Calculations and Key Experiments for Database Verification

Thermodynamic Investigation of New High-Strength Low-Alloy Steels with Heusler Phase Strengthening for Welding and Additive Manufacturing: High-Throughput CALPHAD Calculations and Key Experiments for Database Verification

Interdiffusion Studies in Alloy 617 and 10Cr Steel Joints Using Diffusion Couple Approach and Simulations

Laser-based directed energy deposition and characterisation of cBN-reinforced NiAl-based coatings

Contact Info

Product

Resources

About