NiAl Grains Research Articles

Изучение условий получения прекурсоров из жаропрочного сплава на основе NiAl, предназначенных для 3D технологий

This article is the second in a series of articles devoted to studying the possibilities of preparing high-quality powder materials from heat-resistant light alloys based on refractory monoaluminides of nickel (β-NiAl), ruthenium (β-RuAl) and the FeCrAl system (fechrals) for the production of compact samples/products of complex shapes using additive technologies with minimal final machining. Additive technologies are based on the use of spherical precursor micropowders with a regulated granulometric composition, good fluidity and an oxide-free surface. In the first article, the possibilities of obtaining precursors from RuAl-based alloys by plasma spheroidization of powders obtained by crushing mixtures from scrap samples of RuAl-based alloys with various additives were considered. This article examines the possibility of obtaining precursors from NiAl-based alloys by plasma spheroidization of powders obtained by crushing mixtures from scrap samples of NiAl-based alloys with various additives. It has been shown that grinding and subsequent grinding of scrap powders in an attritor makes it possible to obtain precursors using the “attrition + plasma spheroidization” scheme with characteristics that make them suitable for additive manufacturing (perfectly round shape, surface almost free of oxides, phase composition – solid solution grains on based on NiAl with thin layers of Ni3Al of nano-sized thickness). The non-uniform distribution of alloying elements in NiAl grains is caused by the short duration (5 hours) of grinding the initial powders of scrap ingots of various compositions obtained using foundry technology. This can be corrected by increasing the grinding duration to 15 hours, which will require the use of the “attrition + granulation + plasma spheroidization” scheme, since the proportion of dispersed powders that must be included in circulation will increase. It has been shown that preliminary reaction alloying in the liquid phase (vacuum arc melting), including the use of recycled materials (scrap alloy samples) as starting materials, allows one to vary the alloy compositions over a wide range, using small volumes of material, and does not require specialized equipment.

Chemical reactions of Ni/Al multilayers upon ultrahigh compressive load at ambient temperature

Energetic multilayers are peculiarized by their self-propagation reactions when giving them a thermal pulse. This work reports the chemical reactions of Ni/Al energetic multilayers can be triggered upon ultrahigh compressive load (stress >1 GPa) at ambient temperature, which is realized by micro-compressions of Ni/Al micropillars with equal molar ratio. Detailed microscopic characterizations evidence monolayer reactions of Ni20Al30 and Ni110Al140 (NixAly: x and y are average thickness of individual layers in nanometer) are triggered, forming a stoichiometric NiAl phase after micropillar compression. The as-observed reactions must be triggered by ultrahigh compressive loads, which aid for nucleation of NiAl grains at atomic intermixing zones of Ni-Al interfaces. Once occurrence, the grain growth is self-sustained by the released heat during NiAl formation. The grain textures depend strongly on the deformation extent. The self-sustained process is terminated until the whole micropillar is reacted. Analogous chemical reactions are not observed in the thickest Ni450Al620 micropillar where atomic intermixing is absent. The comparison highlights the critical role of ultrahigh compressive load to trigger monolayer reactions of Ni/Al multilayers, and could forward the advance of Ni/Al energetic multilayers for diffusion welding purpose.

Thermomechanical properties and the deformation mechanism of nickel monoaluminide-based alloys produced by L-PBF in combination with gasostatic treatment and aging

The synthesized NiAl-based material was manufactured by laser powder bed fusion (L-PBF) followed by gasostatic treatment and aging using spheroidized CompoNiAl-M6 (NiAl–8Cr–6Co–1Nb-0.9Hf) alloy powder (the 20–50 μm fraction). The structure was examined by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED); nanoparticles of the refractory phases were identified. The compressive mechanical properties of the alloy were measured at 20, 800, 900, and 1000 °C. Doping with niobium and hafnium was shown to strengthen the alloy with fine-grained Laves and Heusler phases, as well as the (HfxNby)C carbide phase, which reduce the size of NiAl grains and prevent grain boundary diffusion. Due to this fact, the material can be used at temperatures above 800 °C. Ultimate compressive strength (σb) at 900 °C was 575 MPa, while being 260 MPa at 1000 °C. The dislocation substructure of the deformed sample was examined, and the predominant deformation mechanisms (dislocation glide, dislocation climb, and shear of the crystal lattice of the matrix phase) were identified. In situ TEM nanotensile testing revealed that fine-grained refractory phases increase σb from 1360 MPa to 1870 MPa. Clusters and agglomerates of strengthening phases act as stress concentrators and cause premature alloy failure because of stress localization at the particle interface.

High temperature oxidation resistance of laser shock modified NiAlHf metallic bond layer

The growth state of the thermally grown oxide (TGO) in thermal barrier coatings (TBC) has a crucial influence on the lifetime of TBC. Laser shock processing (LSP) is a new method for modifying the metallic bond layer. In this paper, NiAlHf coatings were modified through LSP. The effect of LSP on TGO formation in the early oxidation phase, the growth state of TGO at the long oxidation stage and the distribution of Hf element within the NiAlHf coatings after LSP were investigated. The results show that LSP successfully induce two effects on NiAlHf coatings. (1) The original oxide particles on the coatings surface are smaller and distribute more densely after LSP. In the oxidation process, these smaller and denser particles act as nucleation points, which make it easier for them to grow rapidly into a continuous oxide film. (2) LSP introduces high density dislocation lines, dislocation cells, sub-grain boundaries and other crystal defects, which provides more short diffusion channels for the selective oxidation of Al element and promotes the growth of oxide films. Both of these effects promote the rapid formation of a dense, continuous and homogeneous oxide film during the early oxidation stages. In addition, Hf element in the No-LSP samples mainly precipitate along the NiAl grain boundaries during the long-time oxidation process. This tends to cause the accumulation of Hf-rich oxides and accelerates the cracking of the oxide film. In contrast, LSP-induced crystal defects allow Hf-rich oxides uniformly distribute within the coatings. The uniform distribution of Hf-rich oxides is beneficial for improving the oxidation resistance of TGO films.

Precipitation of homogeneous nanoscale HfRe2 in NiAl by strain-induced precipitation

The precipitation of homogeneous nanoscale HfRe2 in NiAl grains was achieved by strain-induced precipitation at 1000 °C with a strain rate of 0.001 s−1. HfRe2 could not be precipitated under separate heating at 1000 °C, as the deformation increased, HfRe2 began to precipitate and gradually increased in size due to Ostwald ripening. The increase in hardness confirmed the occurrence of precipitation processes. A detailed discussion of the phase composition of the precipitates and their orientation relationship with the matrix was performed. The lattice mismatch at the NiAl111//HfRe227¯55.36⊥HfRe227¯53 interface was calculated to be only 3.90% based on the Bramfitt two-dimensional lattice mismatch theory, which demonstrated that HfRe2 could precipitate with NiAl as a heterogeneous nucleus.

Aluminum Bronze/Udimet 500 Composites Prepared by Electron-Beam Additive Double-Wire-Feed Manufacturing.

Novel composite CuA19Mn2/Udimet-500 alloy walls with different content of the Udimet 500 were built using electron-beam double-wire-feed additive manufacturing. Intermixing both metals within the melted pool resulted in dissolving nickel and forcing out the aluminum from bronze. The resulting phases were NiAl particles and grains, M23C6/NiAl core/shell particles and Cu-Ni-Al solid solution. Precipitation of these phases resulted in the increased hardness and tensile strength as well as reduced ductility of the composite alloys. Such a hardening resulted in improving the wear resistance as compared to that of source aluminum bronze.

Effect of Heating on the Microstructure of NiAl + CrB2 Coatings Deposited by Mechanical Embedding in a Ball Mill

AbstractThe thickness of NiAl + CrB2 coatings, produced by the mechanical embedding of powders, is limited due to the increasing brittleness of processed materials with milling time. Only the NiAl grain growth and resultant softening of the coating matrix could overcome this problem. Therefore, the effect of heating up to 750°C on the microstructure of NiAl + CrB2 coatings deposited in a ball mill rotating at 350 rpm was investigated through in situ TEM observations. The performed observations proved that defect annihilation starts at ~400°C in large intermetallic grains, which are first attached to the substrate. The growth in NiAl nanocrystallites forming most of the coating is activated only above ~600°C. The average crystallite size was measured to be 5, 14, and 19 nm at RT, 650°C, and 750°C, respectively. The first stage of nano-crystallite growth is relatively fast and connected with the reconstruction of crystallite boundaries using up the amorphous material accumulated in between them. The second stage is slower and involves the expansion of larger crystallites at the expense of smaller ones. The performed experiment proved that heating up to 750°C allows the microstructure recovery and grain coarsening of coatings to be activated.

Влияние углерода на удельное электросопротивление интерметаллидного сплава системы Ni – Al, синтезированного методом электротеплового взрыва под давлением

In this paper, we studied the effect of carbon (3 wt. %) on the electrical resistivity of materials based on Ni − Al and Ni – Al − C synthesized by the electrothermal explosion in the temperature range 300 – 1300 K in a vacuum of 2·10–3 Pa. During an electrothermal explosion, a Ni – Al-based melt is formed in a powder reactive medium, in which carbon is dissolved. It is shown that during the crystallization of the final product, due to its low solubility in NiAl, carbon is located on the surface of intermetallic NiAl grains in the form of multilayer graphite nanofilms 50 – 80 nm thick, filling the intergranular space. It is shown that the synthesized materials have a metallic conductivity, and the electrical resistivity in the measured temperature range of 300 – 1300 K increases monotonically for the Ni – Al-based alloy from 16 to 40 mW·cm and for the carbon-containing Ni – Al – C material from 22 to 60 mW·cm. The temperature coefficient of resistance (TCS) also increases from 1.45·10–3 K–1 for NiAl to 1.77·10–3 K–1 for NiAl/C. The slope of the resistivity curves in the studied temperature range of 300 – 1300 K remains constant and is well described by a linear function.

Intermetallic/Ceramic Composites Synthesized from Al–Ni–Ti Combustion with B4C Addition

The fabrication of intermetallic/ceramic composites by combustion synthesis in the mode of self-propagating high-temperature synthesis (SHS) was investigated in the Al–Ni–Ti system with the addition of B4C. Two reaction systems were employed: one was used to produce the composites of xNiAl–2TiB2–TiC with x = 2–7, and the other was used to synthesize yNi3Al–2TiB2–TiC with y = 2–7. The reaction mechanism of the Al–Ni–Ti system was strongly influenced by the presence of B4C. The reaction of B4C with Ti was highly exothermic, so the reaction temperature and combustion velocity decreased due to increasing levels of Ni and Al in the reactant mixture. The activation energies of Ea = 110.6 and 172.1 kJ/mol were obtained for the fabrication of NiAl- and Ni3Al-based composites, respectively, by the SHS reaction. The XRD (X-ray diffraction) analysis showed an in situ formation of intermetallic (NiAl and Ni3Al) and ceramic phases (TiB2 and TiC) and confirmed no reactions taking place between Ti and Al or Ni. The microstructure of the product revealed large NiAl and Ni3Al grains and small TiB2 and TiC particles. With the addition of TiB2 and TiC, the hardness of NiAl and Ni3Al was considerably increased and the toughness was also improved.

Influence of aging and HIP treatment on the structure and properties of NiAl-based turbine blades manufactured by laser powder bed fusion

The parameters and strategy of laser powder bed fusion (LPBF) applied in the manufacture of turbine rotor blade models using an innovative Ni41Al41Cr12Co6 alloy were optimised. The effect of exposure to heat treatment by aging and hot isostatic pressing (HIP) on the evolution of structural phase transformations was studied by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR TEM). HIP eliminates the structural anisotropy and facilitates the segregation of 0.02–1.5 μm coherent α-Cr precipitates oriented along the NiAl <011> direction. Nanoparticles of the Hf and Heusler phase Ni2AlHf were predominantly redistributed from the boundaries equiaxial with the NiAl grains, which increased the elevated-temperature strength of the alloy. The mechanical properties were studied in the temperature range of 923–1273 K. The temperature-force dependence of the steady-state creep rate, activation energy for creep, and mechanisms of plastic strain accumulation were determined. The temperature dependences of the Young's modulus and offset yield stress were plotted. It was found that the post-treatment of the aged LPBF- built blades by HIP had a positive influence on the resistance to plastic deformation. The high-temperature strength of the rotor blade material fabricated by LPBF + aging + HIP was higher than that of the as-HIP and as-LPBF + aging material by 85 K. The temperature-force operating conditions (over 100,000 h) at a plastic strain less than 1 % were identified.

NiAl-B composites with nanocrystalline intermetallic matrix produced by mechanical alloying and consolidation

Powder mixtures with equiatomic Ni–Al stoichiometry and with the addition of 5, 10, 20 and 30 vol% of boron were mechanically alloyed in a high-energy SPEX mill. Differential scanning calorimetry (DSC) was used for examination of the thermal behaviour of the milled powders. The mechanically alloyed powders and powders after DSC examinations were investigated by X-ray diffraction (XRD). For all the powder mixtures, a nanocrystalline NiAl intermetallic phase was formed during milling. With the increase of boron concentration in the mixtures, more intense refinement of the NiAl grain size during mechanical alloying was observed. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) examinations showed that the produced powders have composite structure, with boron particles uniformly distributed in the nanocrystalline NiAl intermetallic matrix. The density of the composite powders decreases with the increase of boron content, following the rule of mixture.The produced powders were subjected to consolidation by hot-pressing at 800 °C under the pressure of 7.7 GPa for 180 s. The produced bulk materials were investigated by XRD, SEM and EDS as well as characterised by hardness, density and open porosity measurements. It was found that during applied consolidation process the nanocrystalline structure of the NiAl matrix was maintained. The average hardness of the bulk composite samples is in the range of 10.58–12.6 GPa, depending on boron content, increases with the increase of boron content, and is higher than that of the NiAl intermetallic reference sample (9.53 GPa). The density of the bulk composite samples is the same as that of the corresponding powders after milling, decreases with the increase of boron content and is lower than that of the NiAl reference sample. To the best of our knowledge, the NiAl-B composites with nanocrystalline intermetallic matrix have been produced for the first time.

Processing of Ni–Al intermetallic with 2D carbon components

We investigated the peculiarities of the combustion synthesis (or self-propagating high-temperature synthesis − SHS) as well as the structure and phase formation in the Ni–Al–C system. Different carbon components (soot, graphite, carbon nanotubes) were used for synthesis of Ni–Al based intermetallic materials. The synthesized materials were characterized by X-Ray diffraction and SEM analysis confirmed the presence of nanolayered graphite films on the surface of the NiAl intermetallic grains. The data of SEM analysis demonstrated that carbon predominantly located along the boundaries of intermetallic NiAl grains forms a continuous multilayered film on their surface with a thickness of about 60–70 nm. Ni and Al are melted in contact with a carbon at a combustion temperature to saturate with carbon at a concentration corresponds to the binary phase diagram of metal–carbon.

Influence of Ho and Hf on the microstructure and mechanical properties of NiAl and NiAl-Cr(Mo) eutectic alloy

In the present paper, the Ho and Hf was synergistically added in the NiAl and NiAl-Cr(Mo) eutectic alloy fabricated by conventional casting technology. Their microstructure, precipitates and mechanical properties were investigated. The results exhibit that the solid solubility of Ho in NiAl is so low that minor addition of Ho in NiAl would lead to the formation of Ni2Al3Ho and Ni3.5Al1.5Ho phases, which both have the hexagonal crystal structure. The synergistic addition of Hf and Ho would lead to the precipitates of Ni2AlHf and Ni2Al3Ho along NiAl grain boundary and forms the skeleton structure. The synergistic addition of Hf and Ho in NiAl-Cr(Mo) eutectic alloy refines the NiAl/Cr(Mo) eutectic lamella but coarsens the NiAl and Cr(Mo) phases in the intercellular region. The Ni2AlHf and Ni2Al3Ho mainly precipitate along the NiAl/Cr(Mo) phase interface in the intercellular region. Moreover, the synergistic addition of Hf and Ho promotes the formation of coarse NiAl particle in the Cr(Mo) phase. The synergistic addition of Hf and Ho increases the microhardness of NiAl and NiAl-Cr(Mo) eutectic alloy. In addition, they also improve the strength of the NiAl-Cr(Mo) eutectic alloy at elevated temperature but the bulk precipitates along the phase interface are apt to be the initiation of the cracks.

Microstructural Characterization of Dissimilar Titanium Alloys Joints Using Ni/Al Nanolayers

This study demonstrates the potential of the use of Ni/Al nanolayers for joining dissimilar titanium alloys. For this purpose, a detailed microstructural characterization of the diffusion bonding interfaces of TiAl to Ti6Al4V, TiAl to TiNi and TiNi to Ti6Al4V was carried out. The nanolayers (alternated aluminum and nickel (Ni-7V wt.%) layers) were deposited onto the base material surfaces. Diffusion bonding was performed at 700 and 800 °C under pressures ranging from 5 to 40 MPa and at dwell times between 60 and 180 min. Microstructural characterization was performed using high resolution transmission and scanning electron microscopies. The results revealed that dissimilar titanium joints (TiAl to Ti6Al4V, TiAl to TiNi and TiNi to Ti6Al4V) assisted by Ni/Al nanolayers can be obtained successfully at 800 °C for 60 min using a pressure of 20 MPa. The bond interfaces are thin (less than 10 µm) and mainly composed of NiAl grains with a few nanometric grains of Al8V5. Thin layers of Al-Ni-Ti intermetallic compounds were formed adjacent to the base materials due to their reaction with the nanolayers.

Influence of rhenium addition on microstructure, mechanical properties and oxidation resistance of NiAl obtained by powder metallurgy

The search for new materials capable of replacing nickel-based superalloys in aerospace applications has increased rapidly in the recent years. One of the candidates for this purpose is nickel aluminide NiAl provided that its main drawback, namely the inferior fracture toughness at room temperature is overcome. We propose rhenium as an addition to NiAl to improve its mechanical properties without compromising on the oxidation resistance. Two powder metallurgy techniques (HP and SPS) were used to obtain NiAl/Re sinters. Small amounts of rhenium (0.6 at%; 1.25 at%; 1.5 at%) almost doubled the flexural strength of NiAl and improved its fracture toughness by 60%. Microscopic investigations revealed rhenium particles at the boundaries of NiAl grains resulting in an enhanced fracture toughness. Mass changes during oxidation at 900 °C, 1100 °C and 1300 °C were relatively low. Plausible mechanisms of the fracture toughness enhancement and the oxidation behavior are discussed.

Microstructure and thermomechanical behavior of Heusler phase Ni2AlHf-strengthened NiAl-Cr(Co) alloy produced by HIP of plasma-spheroidized powder

This study demonstrates that homogeneous high-purity micropowders with grain size of 10–45 µm from refractory NiAl-Cr(Co)-Hf alloy can be produced by combustion elemental synthesis and further treated in a thermal plasma flow. The optimal parameters of plasma spheroidization of the synthesized powders are shown at which the resulting spherical alloy particles are characterized by high sphericity (~ 98%) and the absence of satellites or internal porosity. The spherical powders were consolidated by HIP. The alloy structure was investigated by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The fine structure and features of segregation of hardening nanoparticles of Ni2AlHf (the Heusler phase) and hafnium solid solution (ssHf) in the NiAl matrix were thoroughly studied. Furthermore, in situ examination of structural phase transformations occurring in the as-HIP NiAl-based alloy was carried out upon heating in the temperature range of 25–850 °C. The α-Cr phase nanoparticles are formed inside the NiAl grains via two different mechanisms: (1) spinodal decomposition of solid solution at 250–450 °C resulting in segregation of the Guinier-Preston zone rich in Cr and its subsequent transformation into α-Cr precipitates 25–170 nm in size; (2) heterogeneous nucleation and growth of α-Cr nanocrystallites 7–40 nm long on prismatic dislocation loops at 750–850 °C.The thermomechanical properties of the alloy were studied in the temperature range of 596–1100 °C on a Gleeble System 3800 testing system. The correlation between the thermal load and the high-temperature creep rate, as well as the temperature dependences of the Young's modulus (E), the offset yield strength (σ0.2), and the rate sensitivity coefficient (m), were ascertained. The Young's modulus (E), the ultimate tensile strength, the offset yield strength σ0.2, and the proportional limit of the alloy being examined during uniaxial compression test of a cylindrical sample at 750 °C and at true strain rate of ~ 0.01 s−1 were as high as 137.8 GPa, 682, 455 and 358 MPa, respectively.

Effect of P impurity on mechanical properties of NiAl Σ5 grain boundary: From perspectives of stress and energy**Project supported by the National Natural Science Foundation of China (Grant Nos. 11404396 and 51201181) and the Subject Construction Fund of Civil Aviation University of China (Grant No. 000032041102).

In this paper, we employ the first-principle total energy method to investigate the effect of P impurity on mechanical properties of NiAl grain boundary (GB). According to “energy”, the segregation of P atom in NiAlΣ5 GB reduces the cleavage energy and embrittlement potential, demonstrating that P impurity embrittles NiAlΣ5 GB. The first-principle computational tensile test is conducted to determine the theoretical tensile strength of NiAlΣ5 GB. It is demonstrated that the maximum ideal tensile strength of NiAlΣ5 GB with P atom segregation is 144.5 GPa, which is lower than that of the pure NiAlΣ5 GB (164.7 GPa). It is indicated that the segregation of P weakens the theoretical strength of NiAlΣ5 GB. The analysis of atomic configuration shows that the GB fracture is caused by the interfacial bond breaking. Moreover, P is identified to weaken the interactions between Al–Al bonds and enhance Ni–Ni bonds.

Epitaxial growth of the intermetallic compound NiAl on low-index Ni surfaces in Ni/Al reactive multilayer nanofoils

Crystal growth in the case of self-propagating reactions in Ni-Al nanofoils was investigated by means of molecular dynamics simulations. We studied the heteroepitaxial growth of NiAl on Ni during mixing and alloying at interfaces. Three low-index Ni surfaces were considered. In the case of the (001) and (111) orientations of Ni, a layer-by-layer formation occurred. Four orientations of NiAl grains were observed in (001) and six in (101). The orientation relationships of NiAl(101) with Ni(001) and with Ni(111) were derived. For the (101) orientation of Ni, massive crystallization was observed in the form of grains tilted in relation to the interface. The microstructure evolution was tracked along with grain orientation dynamics. In all cases, a simple geometric construction based on the relationship between unit cells of Ni and NiAl explains crystal growth specificities. The nucleation process and growth kinetics were also investigated. The present study proves that crystal growth varies considerably, in relation to Ni orientation.

Diffusion Bonding of TiAl to Ti6Al4V Using Nanolayers

Microstructural characterization of TiAl to Ti6Al4V dissimilar diffusion bonds assisted by reactive Ni/Al nanolayers was performed in this study. The nanolayers (alternated Al and Ni) were deposited onto the base material surfaces. Diffusion bonding was performed at 700 and 800 °C under pressures from 5 to 40 MPa and dwell times between 60 and 180 min. Microstructural characterization was performed using high-resolution transmission and scanning electron microscopies. The observations revealed that dissimilar TiAl to Ti6Al4V joints assisted by Ni/Al reactive nanolayers can be obtained successfully at 800 °C during 60 min using a pressure of 20 MPa. The bond interface is thin (less than 10 µm) and is mainly composed of NiAl grains. Thin layers of Al-Ni-Ti intermetallic compounds were formed adjacent to the base materials.

NiAl Oxidation Reaction Processes Studied In Situ Using MEMS-Based Closed-Cell Gas Reaction Transmission Electron Microscopy

The nanoscale oxidation mechanisms and kinetics of a model β-NiAl system were investigated using in situ closed-cell gas reaction scanning transmission electron microscopy (STEM). Here, we directly visualize the dynamic structural and chemical changes that occur during high-temperature oxidation at a high spatial resolution of 50.3Ni–49.7Al (at.%) nanoparticles under static air conditions at 730 Torr with heating up to 750 °C at 5 °C/s. A MEMS-based gas cell system, with microfabricated heater devices and a gas delivery system, was used to reveal site-specific oxidation initiation sites. Through time-resolved annular dark-field STEM imaging, we tracked the nanoscale oxidation kinetics of Al2O3. After oxidation at 750 °C, nucleation of voids at the Ni/Al2O3 interface was observed along a NiAl grain boundary, followed by the formation of faceted NiO crystals. Small faceted cubic crystals of NiO were formed at the initial stage of oxidation at high PO2 due to the outward self-diffusion of Ni2+ ions, followed by the formation of a mixture of metastable and stable α-Al2O3 at the oxide/metal interface that is attributed to a PO2 decrease with oxidation time, which agreed with thermodynamic modeling calculations. The results from these in situ oxidation experiments in the β-NiAl system are in agreement with the established oxidation mechanisms; however, with in situ closed-cell gas microscopy it is now feasible to investigate nanoscale oxidation mechanisms and kinetics in real time and at high spatial resolution and can be broadly applied to understand the basic high-temperature oxidation mechanisms for a wide range of alloy compositions.