The correlation between the atomic structure, microstructure, and macroscopic properties of structural materials remains a core issue in materials research. In recent years, substantial progress has been achieved in constructing accelerator-based neutron sources and related experimental techniques, offering a robust platform for an in-depth understanding of the aforementioned correlation under real-time and in situ conditions. This article reviews the latest advancements in the application of major neutron characterization techniques, including neutron diffraction, Bragg-edge imaging, small-angle neutron scattering, pair distribution function analysis, and quasi-elastic/inelastic neutron scattering, in structural materials. Furthermore, it particularly highlights the origins and evolution of internal stresses during the phase transformations of steels, deformation mechanisms in light metals such as magnesium alloys, and microstructure and residual stress analyses using Bragg-edge imaging. Finally, a brief outlook on future development trends is provided.

Neutron diffraction is an advanced experimental technology relying on the neutron source scientific device, which can obtain statistical information of the internal microstructure of materials in a non-destructive manner. It is an indispensable characterization method for establishing the intrinsic relationship between the microstructure, mesoscopic, and macroscopic structure and performance of materials. At the same time, it is an important method for quantitative non-destructive evaluation of residual stress inside key components of major technologies and equipment. This article briefly introduces the measurement principle and basic methods of neutron diffraction technology, elaborates on the research progress of this technology in material foundation and cutting-edge exploration, and evaluates its position and role in engineering component design, manufacturing, service, and safety assessment. Finally, based on the common requirements for the development of new materials and processes, the development potential of neutron diffraction technology for cross scale and multi parameter analysis is discussed, as well as its future development direction in high-throughput characterization.

Aluminum-based silicon carbide (SiC/Al) composites are widely used in the field of precision optics by virtue of their high specific modulus, high specific strength, and excellent dimensional stability. The dimensional stability of these composites is primarily influenced by macroscopic and microscopic residual stresses induced during the heat treatment process. This study employed neutron diffraction and finite element method (FEM) to investigate the impact of cryogenic cycle treatment on both macroscopic and microscopic residual stresses within the 35%SiC/6092Al composite material in the annealed state. The results of this study will clarify the methods and effects of reducing the residual stress and improving the dimensional stability of precision optical parts. The study focused on the influencing factors such as the number of cryogenic cycles, sample size, reinforcement particle size, and temperature difference of cryogenic cycles. The results show that the deep cryogenic cycles can remarkably reduce the internal stress of SiC/Al composites in the annealed state; as the number of cryogenic cycles increases, the internal stress reduction effect of a single cycle weakens. The cryogenic cycles primarily induce plastic strain in the matrix around particles, thereby influencing the internal stress between the particles and the surrounding matrix. No significant relationship is found between cryogenic cycles and external dimensions. Moreover, the cryogenic cycle barely increases the macroscopic stress of the annealed sample. For composites with equal volume fraction of SiC particles, the reduction in the internal stress after multiple cryogenic cycles is the same regardless of the SiC size. Moreover, the effect of multiple cryogenic cycles on the reduction in internal stress has little to do with the cryogenic cycle temperature difference. Cryogenic cycles at temperatures ranges of 100~-196°C and 200~-196°C exhibit almost identical alterations in internal stress.

A comprehensive understanding of how the addition of SiC particles influences the precipitation-strengthening behaviors of SiC/Al-Zn-Mg-Cu composites is essential for the advancement of high-performance aluminum matrix composites. However, the intrinsic mechanisms have remained unclear for a long time owing to limited characterization methods. Herein, the effect of aging temperatures (100 and 160^oC) on the precipitation behaviors and strengthening mechanisms of SiC/Al-7.5Zn-1.8Mg-1.7Cu (mass fraction, %) composites containing 15%SiC (volume fraction) was investigated using in situ small angle neutron scattering, transmission electron microscopy, and tensile testing. A comparison was also made with the Al-7.5Zn-1.8Mg-1.7Cu alloy. As the aging time extended from 0.5 h to 3 h at 100^oC, the precipitates in the composites evolved from GPI zones to GPI zones + GPII zones, accompanied by a noticeable increase in size. However, the increase in the volume fraction of precipitates was not substantial owing to slow aging kinetics. This increase in both the size and volume fraction of precipitates can enhance the resistance to dislocation cutting through precipitates, thereby improving the precipitation-strengthening capacity of the composites. Aging kinetics accelerated at 160^oC, leading to an increase in both the size and volume fraction of precipitates in the composites with extended aging time. The types of precipitates transitioned from GPII zones + η' phase at 0.5 h to η' phase + η phase at 3 h. Nevertheless, the primary precipitation-strengthening mechanism at this temperature was dislocation bypassing strengthening. Although the expanding volume fraction of precipitates increased the yield strength of the composites, the coarsening of precipitates and the appearance of equilibrium η phase with inferior strengthening capacity imposed limitations on the yield strength increment. Compared with the Al-7.5Zn-1.8Mg-1.7Cu alloy, the composites exhibited low yield strength after aging at 100 and 160^oC for 3 h, albeit with differing mechanisms. During aging at 100^oC, the type and size of precipitates in both materials were roughly the same, but the composites had a lower volume fraction of precipitates owing to Mg consumption caused by SiC/Al interface reactions, thus weakening the precipitation-strengthening capacity. Conversely, during aging at 160^oC, accelerated aging kinetics compensated for the reduction in precipitates volume fraction caused by Mg consumption. However, a low vacancy concentration led to precipitate coarsening and an increased proportion of equilibrium η phase, further weakening the precipitation-strengthening capacity of the composites.

Bulk metallic glasses (BMGs) are exhibit a unique atomic structure and have a long-range disorder but short-to-medium-range order, contrasting sharply with the periodic arrangements found in crystalline materials. This distinct arrangement grants BMGs exceptional properties such as high strength, significant elastic limits, and high resistance to corrosion and wear. However, BMGs are brittle owing to localized shear band propagation during deformation under load, particularly at temperatures below their glass transition temperature. This brittleness restricts their practical applications, prompting researchers to explore methods to enhance their ductility. One prominent approach involves the development of bulk metallic glass composites (BMGCs) via incorporating a secondary phase that effectively mitigates the single shear band instability and promotes multiple shear bands to partake in plastic deformation, significantly enhancing the room-temperature ductility. BMGCs reinforced with W wire are noteworthy owing to the high density and strength of W, making these materials highly applicable in the defense sector. By embedding W wires homogeneously into a BMG matrix such as Vitreloy 1 (Zr_41.2Ti_13.8Cu_12.5Ni_10.0Be_22.5, atomic fraction, %), the resulting composite has high compressive strength and ductility. Despite these benefits, the production of W wire-reinforced BMGCs inevitably introduces thermal residual stresses owing to the differences in the coefficients of thermal expansion of the composite components. These stresses can significantly affect the mechanical properties of the BMGCs. Advanced nondestructive techniques such as neutron diffraction have become indispensable tools for evaluating the internal stress distribution within such materials. Neutron diffraction enables the measurement of stresses deep within the materials, providing a comprehensive view of the entire sample volume, which is crucial for optimizing the manufacturing processes and enhancing the performance of the BMGCs. This work aims to comprehensively investigate the effects of various processing parameters, such as the diameter of the W wires and temperature, on the residual stresses within W wire-reinforced BMGCs. By using neutron diffraction to analyze the effects of annealing treatment of W wires in hydrogen, heat treatment duration of BMGCs, and W wire diameter on residual stresses, this work aims to finely tune the internal stresses during the manufacturing process, thereby laying a foundation for optimizing and improving the material properties of W wire-reinforced BMGCs. The results reveal a strong <110> texture along the axial direction of the W wire and a low refined residual value (R_wp), confirming the accuracy of the refined data. The tempering process demonstrates a complex influence on the control of residual stresses within W wire-reinforced BMGCs. Measurements and analyses of residual stresses after different tempering treatments reveal that a 30 min temper at 200^oC effectively reduces residual stresses. However, extending the tempering duration to 60 min leads to the reaccumulation of stresses owing to complex reactions within the BMGCs. In addition, a comparative analysis of W wire-reinforced BMGCs annealed in the present and absence of hydrogen indicates that the former significantly improves the surface quality of W wires, thereby reducing the residual stresses in the BMGCs. After annealing in hydrogen, the diameter of W wires increases from 0.2 mm to 0.3 mm, which has little effect on the overall stress distribution.

Welding is an essential means of joining structural components to form a new structure. Welding residual stress mainly results from materials expanding or contracting due to temperature variations, which can reduce the life of titanium alloys. Therefore, to reduce undesired residual stress, the welding process and microstructure of the materials involved should be optimized. Titanium alloys play a crucial role in marine and aviation fields due to their excellent corrosion resistance and high specific strength. This work investigates the influence mechanism of the prewelding pretreatment process on the structure, mechanical properties, and residual stress of the electron beam welding joint of a titanium alloy thick plate. The macrostructure and microstructure of titanium alloy welding joints prepared using different pretreatment processes are characterized. Results showed that preheating before welding substantially widens the fusion zone (FZ) and heat-affected zone (HAZ) of the welding joint, coarsening α lamellae in both zones. Thus, the hardness of the FZ and HAZ of the preheated welding joint is reduced to close to that of the base metal. Simultaneously, the strength and toughness of the welding joint is considerably improved such that it is similar to the base metal. The neutron diffraction, deep-hole drilling, and Rostenthal-Norton contour methods are used to measure the residual stress of the electron beam welding joint. The neutron diffraction method exhibits high detection accuracy and can achieve stress monitoring in different zones of the weld seam. Deep-hole drilling is a mechanical strain relief technique for measuring transverse and longitudinal residual stress through component thickness. The Rostenthal-Norton contour method can obtain a three-dimensional stress on the welding joint. A combination of these three measurement techniques can complement and be used to verify each other, providing reasonable data for the residual stress evaluation. The detection results of unpreheated welding joints are compared and analyzed, and the residual stress distribution in the FZ and HAZ zones along different directions is obtained. The FZ is subjected to tensile residual stress along all three directions. Alternatively, the HAZ is subjected to compressive stress along the transverse and longitudinal directions and tensile stress along the normal direction. The residual stress at base metal is small. Additionally, the residual stress results obtained by the deep-hole drilling method for the welding joints using two preheating processes are compared. The results showed that preheating before welding can considerably reduce residual stress at the weld. The reason is discussed in depth. Numerical simulation is used to calculate the changes in the temperature and stress fields under different preheating temperatures. The dynamic change rules of thermal stress under different preheating temperatures are obtained. Results showed that increasing the preheating temperature reduces thermal stress and the thermal expansion mismatch in different areas of the welded joint. Moreover, the microstructure, element distribution, and grain orientation of the FZ and HAZ of joints welded using two pretreatment processes are analyzed. Preheating coarsens the α lamellae and promotes the redistribution of alloy elements, thereby reducing the stress concentration between α and β phases. Besides, variant selection of the HAZ is induced by the preheating process. The number and differences in the orientation of α variants are decreased, thereby reducing the stress concentration between variants.

Because deformed magnesium alloys with low density and desirable mechanical properties can save energy and reduce emissions, they are in considerable demand in industrial applications. However, due to their hcp crystal structure, magnesium alloys have a limited number of slip systems that can be activated at room temperature. At present, many deformed magnesium alloys still face the problems of insufficient formability and poor mechanical anisotropy at room temperature, which limit the development of secondary forming processes. Meanwhile, many reports have proven that regulating the texture of deformed magnesium alloys is an effective strategy to improve their formability. Therefore, this study primarily employs the neutron diffraction technology, combined with microscopic characterization methods such as SEM and EBSD, to systematically study the effects of the minor rare earth element Ce on the microstructure, bulk texture, and mechanical anisotropy of extruded Mg-0.3Al-0.2Ca-0.5Mn magnesium alloy sheet. The results show that as the Ce content increases, second-phase particles in the extruded magnesium alloy sheet gradually transform from Al₈Mn₅ to Ce-containing Al₈Mn₄Ce and Al₁₁Ce₃ particles and the number density of second-phase particles increases remarkably. The addition of 0.05%Ce (mass fraction) did not considerably improve the basal texture of the sheet. However, after the addition of 0.5%Ce, fiber texture components distributed along the transverse direction (TD) are substantially reduced while the texture of (0002) pole figure of the alloy changed from a bimodal basal texture to a bimodal nonbasal texture along the extrusion direction (ED). This nonbasal texture formation is mainly caused by larger Ce-containing second-phase particles (> 1 μm) promoting the particle-stimulated nucleation effect and preferential growth of nonbasal-oriented recrystallized grains. Therefore, when 0.5%Ce is added, the basal texture of the alloy is remarkably optimized, so that the ratio of the tensile yield strength along TD to that along ED is close to 1, implying that the anisotropy of the extruded Mg-0.3Al-0.2Ca-0.5Mn alloy has been substantially reduced by the minor addition of Ce element.

The additively manufactured AlSi10Mg alloy demonstrates considerable residual stresses, adversely affecting the dimensional accuracy, operational safety, and corrosion resistance of the parts. In practical applications, stress relief annealing is necessary to eliminate residual stresses in residual stress-sensitive applications. However, the current understanding of the mechanical properties of the additively manufactured AlSi10Mg alloy after annealing is still limited to the macroscopic level. To further investigate the micromechanical behavior and intrinsic mechanisms of the alloy, this study employed synchrotron X-ray diffraction technology to conduct in situ deformation analysis. This study thoroughly examined the lattice strain and stress evolutions of the Al and Si phases and clarified the individual contribution of each phase to the strain hardening rate of the alloy. In addition, this study quantitatively assessed the evolution of dislocation density and elucidated the influences of annealing heat treatment on the load transfer and dislocation behavior of the additively manufactured AlSi10Mg alloy.

The γ′ and γ′′ phases are crucial strengthening components in Ni-based superalloys. Understanding their precipitation and evolution mechanism during heat treatment is essential for tailoring the mechanical properties of the superalloys. Herein, GH4169 superalloy was used to investigate the precipitation and evolution behaviors of secondary phases during in situ standard heat treatment by time-of-flight small-angle neutron scattering. Further, transmission electron microscopy was employed to observe the secondary phases generated in samples after ex situ heat treatment. Results showed that the secondary phases, including the spherical γ′ phase and coprecipitates (mainly the γ′′/γ′/γ′′ sandwich structure), mostly occurred during the aging treatment. After the formation of coprecipitates during the first aging treatment (AT1), their quantity apparently remained stable during the second aging treatment (AT2). Furthermore, the average size of the γ′ phase and coprecipitates gradually increased during the AT1 stage while remaining almost constant during the AT2 stage. Throughout the aging process, the interface between spherical γ′ phase and γ matrix exhibited a decreased composition fluctuation, while the interface fluctuation of coprecipitates was always significant. Thus, it can be inferred that the precipitation and evolution behaviors of secondary phases are controlled by the element diffusion at the interface.

AerMet100 ultrahigh-strength steel is widely used in aircraft landing gears because of its excellent mechanical properties. Its high strength mainly results from the secondary hardening effect of a large amount of needle-shaped M₂C-type precipitates generated during the alloy tempering process. Given the nanoscale size and coherency with the martensitic matrix, the size and composition of the precipitates in the AerMet100 steel are difficult to extract and accurately characterize by using traditional imaging techniques. In this study, the size, distribution, and composition of M₂C-type needle-like precipitates in AerMet100 steel tempered for 5 h at 454, 482, 486, and 498^oC were quantitatively characterized by combining TEM, XRD, and small-angle neutron scattering (SANS) techniques. By applying a transverse magnetic field of 1.1 T during the SANS experiment and reducing the data along the parallel and perpendicular magnetic field directions, the separation of nuclear and magnetic scattering data was achieved. Model fitting of the nuclear scattering curves revealed an average length of 6-16 nm and an average diameter of 1-2 nm for the needle-like precipitates in the alloy. The volume fraction of the needle-like phase increases with the tempering temperature ranging from 0.54% to 5.19%. Given the nanodomains between the precipitates and matrix phase with spin misalignment, the structural parameters obtained from magnetic scattering data are much bigger than the nuclear ones. Furthermore, by comparing the neutron scattering length densities of the carbides and matrix phases, the possible chemical composition and physical density of the needle-like precipitates within are (Cr_0.4Mo_1.6)C and 8.55 g/cm³, respectively. This study demonstrates nondestructive quantitative neutron scattering analysis of the nanoscale morphology and chemical composition of nanophases in ferromagnetic alloys.

Liquid-liquid phase transition (LLPT) is a universal phenomenon that occurs in different types of liquids. Understanding its mechanism can help solve the long-standing mystery of liquid and amorphous structures. In metallic liquids, LLPT has been widely reported to be observed in the supercooled liquid region in multicomponent alloy systems. However, few observations of LLPT were reported in binary metallic systems, mainly due to the poor thermal stability of these systems in the supercooled liquid region. Herein, the phase transition of Pd₈₂Si₁₈ metallic glass in its supercooled liquid region was studied by in situ synchrotron X-ray scattering and transmission electron microscopy (TEM). The in situ synchrotron diffraction data revealed the precipitation of fcc crystals after 200 s of annealing at 638 K. Before 200 s, the position of the first broad diffraction peak, Q₁, shifted toward lower momentum transfer (Q) values and the peak broadened, indicating the occurrence of LLPT at the initial stage of annealing. The structural changes occurring during LLPT were analyzed based on the pair distribution function; the changes were characterized by a transition from short- to medium-range orders as per the reduced atomic pair distribution function curve G(r). The intensity of peaks up to the fourth nearest neighbor shell in the G(r)curve exhibited different variations trends during LLPT. The peaks were classified into two groups: those indicating an fcc structure and those indicating a six-membered tricapped trigonal prism (6M-TTP; a typical medium-range order observed recently in Pd-based metallic glasses) structure. The number of peaks associated with the 6M-TTP structure gradually decreased during annealing. In contrast, the number of peaks associated with the fcc structure gradually increased at medium-range scale and decreased at short-range scale before 200 s. An analysis of the G(r) peaks indicated that LLPT is characterized by a transition from the 6M-TTP-type atomic cluster to a new type of cluster. This new type of cluster shows an atomic correlation similar to that observed in the fcc structure in the medium-range scale; however, its short-range order deteriorates. Further, high-angle annular dark field scanning TEM images revealed nanoscale structural heterogeneities during LLPT. The SAED and HRTEM results confirmed that the sample annealed for a short duration (i.e., before 200 s) with a nanoscale heterogeneous structure is amorphous, thus demonstrating the coexistence of two liquid phases. Notably, one of the two liquid phases is prone to crystallization under ion milling, thereby forming a crystal-amorphous network structure. The crystals formed due to ion milling exhibit the fcc structure and have the same crystal orientation. This research provides new evidence to unravel the LLPT mechanism in supercooled metallic liquids. Further, it presents a new model for explaining the complex structure and phase transition in metallic liquids.

Environmental barrier coatings (EBCs) enable SiC_f/SiC ceramic matrix composites (CMC) to operate under high-temperature combustion conditions. They reduce the oxidation rate of SiC_f/SiC, the volatilization of the composites due to reaction with water vapor, and the surface temperature of the composites. Rare-earth monosilicates (RE₂SiO₅), owing to their excellent high-temperature durability, low thermal conductivity, and good phase stability, are used as the top layer of EBCs. However, they exhibit a high coefficient of thermal expansion (CTE), leading to thermal mismatch and inducing tensile residual stress (with a magnitude of several hundred MPa) in the coating, resulting in the formation of vertical cracks, which act as extremely-high-diffusivity paths for oxidation species transportation and silica volatilization. Therefore, regulating the CTE of RE₂SiO₅ EBCs and minimizing the CTE mismatch among constituent RE₂SiO₅ layers with SiC_f/SiC CMCs are critical for multilayered EBCs. Through atmospheric plasma spraying, a typical Yb₂SiO₅/Yb₂Si₂O₇/Si coating system and a tri-layer structured multicomponent (Y_1/4Ho_1/4Er_1/4Yb_1/4)₂SiO₅/Yb₂Si₂O₇/Si coating system with better matched CTEs were manufactured. Both the coatings remained adhered to the substrate during deposition and after annealing, and no mud cracks that would compromise the coating gas-tightness quality and delamination cracks were observed at any of the coating interfaces. In thermal cycling tests, (Y_1/4Ho_1/4Er_1/4Yb_1/4)₂SiO₅/Yb₂Si₂O₇/Si coatings showed a lifetime that is three times longer than that of conventional Yb₂SiO₅/Yb₂Si₂O₇/Si coatings. The failure mechanisms in thermal cycling were investigated via the finite element simulation of stress. It was found that the stress in the substrate was low, and the residual thermal stress was mainly concentrated on the top, inter, and bond layers and increased with an increase in temperature. Compared with that of the (Y_1/4Ho_1/4Er_1/4Yb_1/4)₂SiO₅ top coat, the Yb₂SiO₅ top coat showed obviously higher residual tensile stress, which contributed to a higher tendency for mud-crack formation and higher energy release rate, substantially reducing the coating's thermal cycling lifetime. Through neutron powder diffraction and pair distribution function (PDF) analysis, the average and local structures of RE₂SiO₅ were studied. Overall, the average and local structures did not differ significantly, both of which can be described using the C2/c structure. Nevertheless, the PDF results demonstrated some differences in the disorder degree of Si—O and RE—O coordination environments. In particular, Rietveld refinement results of the PDF showed lower local distortion degree of [ORE₄] tetrahedrons when compared with that of the average structure. It is effective to reduce the distortion degree of [ORE₄] tetrahedrons by introducing Y³⁺, Ho³⁺, and Er³⁺ into the Yb³⁺ sites of Yb₂SiO₅, and smaller distortion degrees lead to lower CTE values. Coordinative local disturbances introduced by strategic high-entropy design have been proposed as the key method for CTE regulation.

Aniline is an important chemical raw material widely used in various industries, including medicine, dye manufacturing, and rubber production. Catalytic liquid-phase dhydrogenation of nitrobenzene is a main industrial production method for aniline. However, the separation and recovery of the catalyst from the liquid hydrogenation system remain challenging. Graphene-encapsulated transition-metal nanoparticles (TM@G, where TM = Fe, Co, and Ni) exhibit magnetic separability and electron transfer effects, making them widely applicable in heterogeneous catalysis. In this study, a magnetically separable catalyst support, comprising graphene-encapsulated Ni nanoparticles (Ni@NG), was developed. This support was then loaded with a Pt metal catalyst for efficient catalytic hydrogenation of nitrobenzene to aniline. To fabricate the catalyst support, ethylenediaminetetraacetic acid and Ni(OH)₂ were uniformly mixed in deionized water until the solution turned blue at 90°C. The resulting blue solid precursor was then dried and annealed at 600°C in argon to yield the magnetic support (Ni@NG). The support was then characterized using Raman spectroscopy, TEM, XRD, and XPS. TEM results revealed that the Ni@NG support exhibited a typical core-shell structure (with nanoscale Ni particles as the core and 2-5 layers of graphene as the shell). The Raman spectrum of the Ni@NG support exhibited the characteristic D and G bands of graphene at 1341 and 1604 cm^-1, respectively. Moreover, the XRD spectrum of this support exhibited distinct peaks corresponding to Ni and graphene, while its XPS analysis confirmed the presence of an approximate nitrogen atom concentration of 3.64% in the nitrogen-doped graphene shell. Furthermore, the deposition-precipitation method was employed to synthesize a Pt-loaded Ni@NG catalyst (Pt/Ni@NG), which was later used in the catalytic hydrogenation of nitrobenzene in a liquid-phase reaction. Results revealed that increasing the Pt weight loading (mass fraction) from 0.1% to 0.5% altered the Pt dispersion state from single atoms to clusters and then to particles. In particular, at a Pt weight loading of 0.3%, the Pt/Ni@NG catalyst dominated by Pt clusters exhibited the highest activity for the hydrogenation of nitrobenzene. At this Pt weight loading, the catalyst achieved a turnover frequency of 27239.2 h^-1 at 1 MPa reaction pressure under 30°C, completely converting nitrobenzene to aniline within 60 min. Furthermore, the Pt/Ni@NG catalyst maintained its activity over five testing cycles, attributed to its excellent liquid-phase magnetic separability.

Many binary Cr-Te compounds can be regarded as formed due to varying degrees of ordered vacancies of metal Cr atoms in Cr-Te with the NiAs structure. Among them, Cr₅Te₈ shows two structures: trigonal and monoclinic. This study determined that Cr₅Te₈ grown using the self-flux method shows a trigonal P\overline{\mathrm{3}}m1 crystal structure with lattice constants a = 0.3900 nm and c = 0.5986 nm, as elucidated through the Rietveld refinement of powder X-ray and neutron diffraction patterns. Neutron powder diffraction experiments reveal its collinear ferromagnetic compound, with Cr magnetic moments oriented along the c axis. In addition, it exhibits low negative thermal expansion along the a direction and normal thermal expansion along the c direction. Within the temperature range of 3.3-300 K, using the lowest temperature of 3.3 K as a reference, the average thermal expansion coefficient of Cr₅Te₈ is -10.7 × 10^-6 and 52.4 × 10^-6 K^-1 in the a and c directions, respectively. Cr₅Te₈ crystals oriented along the [101], [302], and [201] directions show near-zero thermal expansion and thus have wide application prospects. The abnormal thermal expansion of Cr₅Te₈ is apparently unrelated to its magnetic order but may be related to the Cr vacancies in the crystal lattice.