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Showing 1 to 20 of 27 for “"Nickel-Based Superalloys"”.
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Recrystallisation in Single Crystal Nickel-Based Superalloys
… during investment casting of single crystal Ni-based superalloys arise from differences in thermal contraction between the metal and ceramic mould-and-core. If deformation is above a critical limit, subsequent solution heat treatment of the alloy causes recrystallisation. Crack nucleation and …
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Influence of surface hardening on single crystal nickel-based superalloys
… (DCR), on the microstructures of single crystal nickel-based superalloys. These alloys have excellent high temperature properties, and consist of a randomly substituted face centred cubic matrix phase known as γ, together with a large volume fraction of an ordered precipitate phase, most often …
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Factors contributing to the yield strength of polycrystalline nickel-based superalloys
Nickel-based superalloys are the material of choice for use in the hottest regions of gas turbine engines due to their inimitable mechanical properties, in particular, high temperature strength. As we become increasingly aware of the environmental consequences of air travel, manufacturers are …
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Wear of Polycrystalline Cubic Boron Nitride Cutting Tools when Machining Nickel-based Superalloys
… rates are observed when using PcBN to machine Ni-based superalloys - in particular Inconel 718. While there have been other studies on the machining of this alloy using PcBN tools, and the types of wear that occur have been described, the underlying mechanisms are still not well understood. With a …
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On the plastic deformation behaviour of nickel-based superalloys: low cycle fatigue and stress orientation effects
… the current knowledge of plastic deformation in nickel-based superalloys, with a focus on dislocation mechanisms and the effect of microstructure. The two main topics treated are the evolution of the dislocation structure during low cycle fatigue and the effect of loading orientation on the …
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A multiscale study on the origins of the Portevin-Le Chatelier effect in polycrystalline nickel-based superalloys
… Chatelier (PLC) effect. This includes nickel-based superalloys, between approximately 200 °C and 600 °C. The PLC effect is widely attributed to Dynamic Strain Ageing (DSA), referring to dislocation pinning effects caused by the diffusion of solute to dislocations, driven by elastic …
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Quantitative assessment of the frictional ignition resistance of metals in high-pressure oxygen
… to compute ignition temperatures for 15 alloys based on published frictional ignition data from NASA White Sands Testing Facility (WSTF). These values were used with the material index to construct property diagrams for ranking intrinsic frictional ignition resistance. The results demonstrate …
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The Role of Slip System Activation on Ni-Based Superalloy High Temperature Fatigue
<p>Nickel-based superalloys are used extensively in the aviation industry, particularly in aircraft engine components. These materials are desirable due to their high strength, resistance to creep, corrosive environment, and high temperature. It has been well documented that material fatigue is …
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Irradiation induced damage in CANDU spacer material Inconel X-750
… in the irradiation-induced instability of γ’ in nickel-based superalloys, the discussion of which is presented in Chapter 10. As one of the most important defect structures induced from irradiation, the stacking-fault-tetrahedra, were dynamically observed and are described in a journal manuscript …
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Mechanism-based constitutive modeling of L1₂ single-crystal plasticity
… composition of the [gamma]' precipitates in nickel-based superalloys and is a major strengthening mechanism contributing to the superalloys' outstanding high-temperature mechanical properties. Many L12-structure crystals present unusual macroscopic mechanical properties, including the …
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Modeling stress accelerated grain boundary oxidation (SAGBO) in INCOLOY alloy 908
… pressure and (2) a new creep law specific to nickel-based superalloys. While the steady state model correctly indicates temperature as one of three leading factors in SAGBO, it fails to capture the effects of the two remaining factors: applied loading and oxygen partial pressure.
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The role of alloying elements on the microstructure and thermal stability of Refractory Metal High Entropy Superalloys
… be needed, beyond the capabilities of current nickel-based superalloys. Therefore, new high temperature alloys are being investigated, including refractory metal high entropy superalloys (RSAs), based on the AlMoNbTaTiVZr system. These alloys comprise nanoscale order-disordered B2+bcc …
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Understanding forgeability in highly reinforced cast-and-wrought superalloys
… forging of highly γ′-reinforced cast-and-wrought nickel-based superalloys. The theory postulates that surface cracking is controlled by the dissolution of the secondary γ′ phase and its subsequent reprecipitation as very fine precipitates upon cooling. The commercial alloy Udimet 720 is used as a …
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The application of positron emission particle tracking to study non-metallic inclusions in metal castings
… better at higher temperatures than current nickel-based superalloys. To achieve weight savings, inertia welding is being trialled for turbine discs but current post weld heat treatments reduce fatigue life. In this investigation, a number of novel post weld heat treatments were trialled …
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Mechanisms of Deformation and Fracture in TiAl: An Atomistic Simulation Study
… they might be capable of replacing heavy nickel-based superalloys. However, so far applications of TiAl alloys have been limited by their poor ductility. Many of the recent studies have focused on the source of this limited ductility and on methods to improve this property. It has been …
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Design Strategies for Improving the Oxidation Resistance of Multi-Principal Element Alloys
Since the early 1940’s, nickel-based superalloys (SA) have been the cornerstone of hightemperature structural alloys due to their unique yield strength, creep life, and oxidation re-sistance when subject to harsh environments exceeding 1000 °C. While they have withstoodthe increasing operation …
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Bondcoat developments for thermal barrier coatings
The prime design considerations for modern nickel based superalloys for use in aero gas-turbine engines, are those of mechanical performance, namely good resistance to creep and fatigue with good toughness and microstructural phase stability. Design of the current generation of superalloys has …
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Gamma prime precipitation modeling and strength responses in powder metallurgy superalloys
Precipitation-hardened nickel-based superalloys have been widely used as high temperature structural materials in gas turbine engine applications for more than 50 years. Powder metallurgy (P/M) technology was introduced as an innovative manufacturing process to overcome severe segregation and poor …
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