Coefficient Of Thermal Expansion Mismatch Research Articles

Self‐Assembled Composite Cathodes with TEC Gradient for Proton‐Conducting Solid Oxide Fuel Cells

AbstractOne of the key challenges for high‐performance proton‐conducting solid oxide fuel cells (H‐SOFCs) is the mismatch in thermal expansion coefficients (TEC) between the cathode and electrolyte. While incorporating negative thermal expansion (NTE) materials can mitigate this issue, mechanical mixing often weakens cathode strength. To address this, a TEC gradient cathode is proposed and successfully implemented by co‐sintering PrBa(Co0.7Fe0.3)2O5‐δ(PBCF) with Y2W3O12 (YWO) in this work. In this work, Ba atoms at the A‐site of PBCF migrated from the lattice, generating A‐site defects. The resulting BaWO4 and Y10W8O21 phases, which have low TEC, are uniformly distributed between PBCF and YWO, forming a TEC gradient composite cathode. In addition, the transition phase captures the A‐site element Ba in the electrolyte layer, optimizing the electrolyte‐cathode interface. The composite cathode exhibits a reduced TEC, closely matching that of the electrolyte, significantly enhancing interface bonding, thereby providing a lower ohmic resistance of 0.051 Ω cm2 and a higher power density of 1.88 W cm−2 at 700 °C. Remarkably, thermal cycling tests conducted under temperature switching conditions demonstrate the composite cathode's long‐term thermal and chemical stability.

Continuously tunable negative pressure for engineering high-symmetry nanocrystalline phases

In this work, the phenomenon of strain induced by a mismatch in thermal expansion coefficients between a thin film and its substrate is harnessed in a new context, replacing the canonical planar support with a three-dimensional (3-D), nanoconfining scaffold in which we embed a material of interest. In this manner, we demonstrate a general approach to exert a continuously tunable, triaxial, tensile strain, defying the Poisson ratio of the embedded material and achieving the exotic condition of "negative pressure." This approach is hypothetically generalizable to materials of low modulus and high thermal expansion coefficient, and we use it here to achieve negative pressure in perovskite-phase CsPbI3 embedded within the cylindrical pores of anodic aluminum oxide membranes. Through controlled thermal hysteresis, the perovskite crystal structure can be continuously tuned toward higher symmetry when confined in a scaffold with pore size <40 nm, in contrast with the symmetry-reducing action of any other mechanical perturbation. We use this effect to control the octahedral rotation angle that is critical to the remarkable photovoltaic attributes of halide perovskites. Under hundreds of megapascals of apparent negative pressure, the bandgap tunability is observed to follow the same quantitative trend observed for hydrostatic positive pressure, exploring the negative pressure region and demonstrating the relative dominance of bond stretching effects over average octahedral rotation angle on electronic structure. This study reveals and quantifies the structural and electronic consequences of 3D tensile strain present by design and provides a framework for understanding adventitious strain present in all nanocomposite materials.

Preparation and optimization of La0.6Sr0.4Fe1-yCoyO3-δ cathodes for intermediate temperature solid oxide fuel cells

It is shown in this work that a synthetic route based on the auto-combustion of an ethylene glycol-metal nitrate polymerized gel precursor can be efficiently used to easily produce a range of La0.6Sr0.4Fe1-yCoyO3-δ nanopowders at moderate temperatures. We have been able to determine on air-sintered samples the effect of sintering temperature on the microstructure. At sintering temperatures as low as 1100 to1200 °C, grains are well defined with a uniform round spherical morphology and have a homogeneous sub-micrometer size distribution showing a highly densified microstructure. The electronic conductivity and thermal expansion coefficients (TEC) of sintered LSFC samples have been determined according to the variation of Fe/Co composition. Both measures clearly increase with the Co content. These materials also must exhibit chemical stability with electrolytes, most commonly used for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this way, the material as obtained is optimized in terms of chemical homogeneity and good stoichiometric control, microstructural characteristics of sintered samples, and finally the adequate Cobalt content to avoid high TEC mismatch with other components of the SOFC. This is a crucial issue as it causes an important thermo¬mechanical stress; promote extensive microcraking and significant performance degradation. Finally, these cathodes must exhibit acceptable electrochemical parameters for use in IT-SOFC.

Enhancing sapphire/Kovar alloy brazed joint through combined effect of TiB whisker reinforcement and surface micro-nano structures

The brazed joining between Kovar alloy and sapphire was successfully achieved by using TiB whisker reinforcement and applying the surface micro-nano structure. We systematically studied the composition and mechanical properties of Kovar/Sapphire joint. The typical interfacial structure of the joint brazed at 825 °C for 10 min was determined as Sapphire/ γ-TiO/ Ti3(Cu,Al)3O/ Ag(s,s) + Cu(s,s) + TiB/ Ti2Cu + TiFe2 + TiNi3/ Kovar alloy. The addition of B forms tiny TiB whisker reinforcement phase in situ, which refines the interface structure. The presence of micro-nano structures improves the interface products on the sapphire side: reducing the generation of Ti3(Cu,Al)3O and replacing it with γ-TiO. This makes the phase transition on the sapphire side smoother and reduces thermal expansion coefficient mismatch, thereby enhancing joint strength. Under suitable brazing parameters, the maximum shear strength of the joint is 137 MPa. This study provides new insights for optimizing and improving connections between sapphire ceramics and metals, with potential applications in more ceramic/metal joining.

Design and Architecture Definition for Advanced 3D Fan-Out Wafer-Level Packaging

Advanced 2.5D/3D wafer-level fan-out packaging technologies have been studied widely in literature and industry in recent years. Miniaturization, reduction in manufacturing costs, improvement in performance, and lower power consumption using packaging technologies drive increase in interconnect density and pitch scaling. Heterogeneous systems in package used in advanced packaging often include a combination of silicon, epoxy underfill or mold compounds, and organic or inorganic passivation or redistribution layers. This heterogeneity poses challenges with manufacturability, process selection, package architecture, and test vehicle design. The coefficient of thermal expansion mismatch, wafer warpage, and wafer yield are some of the critical process challenges. Delamination of silicon side wall or passivation to epoxy underfill or mold compound, joint fatigue are critical reliability challenges. This article explores various processes and reliability challenges with 3D wafer-level fan-out packaging and provides package design and architecture guidelines to overcome these failure modes. Stacked die-to-wafer test vehicles have been used for data collection. Different assembly materials, processes, and tooling have been evaluated to define comprehensive design rules.

The effect of in situ-synthesized Y2SiO5 on the thermal shock resistance of Y2O3 ceramic materials

Y2O3 ceramics are increasingly recognized for their excellent vacuum stability and high-temperature chemical stability in the field of functional materials research. However, their poor thermal shock resistance renders them susceptible to spalling and damage during use, thus restricting further applications. To address this issue, the low thermal expansion coefficients of Y2SiO5 materials were leveraged. Through an in situ reaction between SiO2 and Y2O3, a Y2SiO5 phase was generated that induced a thermal expansion mismatch with Y2O3, thereby enhancing the thermal shock resistance of the ceramic. Using Y2O3 fine powder as the primary material, silica sol and nano-SiO2 were selected as reactive silicon sources to prepare Y2O3–Y2SiO5 composite ceramics at 1750 °C. The impact of the different silicon sources and Y2SiO5 phase content on the microstructure, mechanical, and thermal properties of the composite ceramics was studied. The results demonstrated that the in situ formation of Y2SiO5 significantly improved the thermal shock resistance of the composite ceramic. Specifically, increasing the SiO2 content led to a gradual rise in the volume fraction of Y2SiO5 formed between Y2O3 grains, thereby increasing the residual flexural strength and enhancing the hardness and elastic modulus. The low thermal expansion coefficient of Y2SiO5 reduced the overall thermal expansion coefficient of the composite material, thereby improving the thermal shock resistance. Moreover, the thermal expansion coefficient mismatch between the Y2O3 and Y2SiO5 phases induced numerous microcracks within the material, providing thermal stress relief within the microcracks and markedly improving the resistance of the ceramic to thermal shock.

Thermal cycling characterization of an integrated low-inductance GaN eHEMT power module

To exploit the potential of wide-bandgap semiconductors in high-frequency applications, innovative packaging designs are developed to minimize the parasitic inductance of power modules. This study presents an integrated power module with a hybrid PCB/DBC structure, which uses top-side cooling prepackaged GaN enhancement-mode high-electron-mobility transistors. The module achieves a remarkably low parasitic inductance of 2.65 nH. However, there is relatively scarce research on the reliability of this heterostructure, particularly its sensitivity to thermomechanical stress due to the coefficients of thermal expansion mismatch among material interfaces. In this work, the thermal cycling characteristics of the integrated power module are comprehensively investigated. Electrical and thermal parameters were periodically and separately measured offline on a simplified package to monitor the health conditions and decouple possible synergy and competition effects among the failure modes from all packaging components. A thorough failure analysis was conducted using nondestructive visual inspections and scanning acoustic microscopy, complemented by destructive cross-sectional examination and scanning electron microscopy. The findings identified the delamination of the DBC upper copper layer, which exhibited a conchoidal fracture interface, as the primary factor that contributed to the failure of the power module with increased thermal resistance. Furthermore, the study dissected its initiation and propagation mechanisms. This investigation provides valuable insights for the development of more reliable low-inductance power module designs.

High-performance GaN ultraviolet polarization-sensitive photodetector based on ferroelectric polarization LiNbO3

High responsivity ultraviolet (UV) photodetectors (PDs) are essential for abundant civilian and military applications. Gallium nitride (GaN) has emerged as an ideal material for UV PD fabrication due to its favorable properties. However, the quality of GaN epitaxial layers significantly impacts device performance and reliability. Sapphire-based GaN epitaxial growth technology enables the realization of high-quality GaN epitaxial layers, making it the preferred choice for GaN substrates. Nonetheless, the thermal expansion coefficient mismatch between sapphire and GaN can lead to crystal mismatch and stress accumulation at high temperatures, affecting device performance and reliability. In contrast, lithium niobate (LiNbO3) exhibits similar coefficients of thermal expansion to GaN, mitigating crystal mismatch and stress accumulation issues. Here, we report the realization of a GaN UV PD by laminating GaN membrane onto ferroelectric LiNbO3 through selective electrochemical etching of the sapphire-based GaN epitaxial film. The LiNbO3-based GaN PD achieves a specific high on/off ratio of 107. At a 5 V bias voltage, the device exhibits a high peak responsivity of 1.712 × 103 A/W under 325 nm laser illumination. Furthermore, the device demonstrates excellent performance for polarization light detection, with a polarization ratio of approximately 54.95. Exploiting the local ferroelectric polarization of x-cut LiNbO3, the photogenerated electron–hole pairs in GaN are efficiently separated by the electrostatic field from the polarization of ferroelectric LiNbO3, resulting in enhanced light-to-electric conversion efficiency. Our work presents a method for fabricating high responsivity GaN-based UV PD, showcasing the potential of integrating ferroelectric LiNbO3 to enhance device performance.

Mechanical property analysis and optimization of nano-hydroxyapatite coated carbon fiber reinforced hydroxyapatite composites

Carbon fiber (CF) is one of ideal reinforcements to hydroxyapatite (HA) owing to its unique structure, excellent biocompatibility and high mechanical properties. However, the mechanical property of CF reinforced HA (CF/HA) composites cannot be effectively improved due to the mismatch in surface properties and thermal expansion coefficients between CF and HA. In order to solve the problems, nano-hydroxyapatite (nHA) coating with different thickness was fabricated on the CF surface. The effect of the coating thickness on mechanical property of nHA-coated CF/HA composites was studied by finite element analysis. The CF with proper nHA coating thickness was subsequently used to reinforce HA. The compressive strength of nHA-coated CF/HA composites was approximately 97.3 % and 164.6 % higher than those of the uncoated CF/HA composites and pure HA ceramics, respectively. The interface properties and crack propagation were analyzed by cohesive element in the finite element analysis. The toughening mechanism of the composites included interfacial debonding, crack deflection, crack branching, and crack bridging. The mechanical properties of nHA-coated CF/HA composites were enhanced due to the strong interfacial bonding strength and reducing cracking in HA matrix. The prepared nHA-coated CF/HA composites satisfy the requirement of the mechanical properties of human load-bearing bone. It can be used to prepare cages, plates, screws, pins and other compact bone substitute parts in bone grafting. The study provided a method for construction of nHA-coated CF/HA composites with the designed properties by adjusting the nHA coating on the fiber and can be used to design other fibers reinforced ceramic matrix composites.

Improved SOFC performance by enhancing cathode/electrolyte bonding and grain refinement of cathode with thermal expansion offset

The thermal expansion coefficient (TEC) mismatch between the cathode and electrolyte presents significant challenge to the thermo-mechanical stability of commercial solid oxide fuel cells (SOFCs). Here a thermal expansion offset composite cathode designated as Ba0.5Sr0.5FeO3-δ (BSF)-xNdMnO3-δ (NM) (x = 0–40 wt%) is developed to address this issue. For the first time, the phase boundary between heterogeneous oxides and the grain size of composite cathode are quantitatively studied with the electron backscatter diffraction (EBSD) technology. For x = 20 wt%, the TEC of cathode decreases by 41 % while the peeling strength of cathode/electrolyte interface increases by 87 %. The highest peak power density (PPD) is achieved for BSF-20NM cathode (1266 mW cm−2 at 650 °C), which is 81 % higher than that for BSF one. Meanwhile, markedly enhanced long-term and thermal cycling stability is obtained. The comprehensive results suggest that both the increased TPB length by enhanced cathode/electrolyte bonding and grain refinement of composite cathode should be responsible for the markedly improved performance and stability.

Microstructural Modifications and Failure Mechanisms of an Aluminum‐Based Abradable Coating System during Isothermal and Cyclic Aging

Abradable systems are used in the aeronautical industry to improve the efficiency of gas turbine. Those materials are exposed in service to temperature up to 450 °C. The increase in gas turbine efficiency requires to increase the operating temperature and therefore the service temperature of abradable coating. The present study focuses on the isothermal and cyclic thermal aging of the Al–Si abradable coating system in a laboratory air at high temperature up to 500 °C. The investigation encompasses the microstructural evolution, phase transformation, and the formation of cracks, along with their interrelated effects. During aging, silicon particles precipitate in the abradable top coat. In addition, coarsening of those particles is observed and the coarsening kinetics appears to be faster in cyclic thermal aging conditions compared to isothermal aging. During cyclic and isothermal aging, brittle aluminides develope at the abradable top–coat/bond–coat interface, due to the interdiffusion of Al and Ni species. During cyclic aging, thermal cycles create thermomechanical stress at the top‐coat/bont‐coat interface due to coefficient of thermal expansion mismatch between the Al‐Si deposit and intermetallic phases. The stress generated results in the formation of cracks and porosities at the top–coat/bond–coat interface resulting in a dramatic failure of the system.

Giant Thermomechanical Bandgap Modulation in Quasi‐2D Tellurium

AbstractLattice deformation via substrate‐driven mechanical straining of 2D materials can profoundly modulate their bandgap by altering the electronic band structure. However, such bandgap modulation is typically short‐lived and weak due to substrate slippage, which restores lattice symmetry and limits strain transfer. Here, it is shown that a non‐volatile thermomechanical strain induced during hot‐press synthesis results in giant modulation of the inherent bandgap in quasi‐2D tellurium nanoflakes (TeNFs). By leveraging the thermal expansion coefficient (TEC) mismatch and maintaining a pressure‐enforced non‐slip condition between TeNFs and the substrate, a non‐volatile and anisotropic compressive strain is attained with ε = −4.01% along zigzag lattice orientation and average biaxial strain of −3.46%. This results in a massive permanent bandgap modulation of 2.3 eV at a rate S (ΔEg) of up to 815 meV/% (TeNF/ITO), exceeding the highest reported values by 200%. Furthermore, TeNFs display long‐term strain retention and exhibit robust band‐to‐band blue photoemission featuring an intrinsic quantum efficiency of 80%. The results show that non‐volatile thermomechanical straining is an efficient substrate‐based bandgap modulation technique scalable to other 2D semiconductors and van der Waals materials for on‐demand nano‐optoelectronic properties.

Photo‐Directed Growth of Surface Micro‐Patterns on Photosensitive Semicrystalline Polymers

AbstractPatterning polymeric materials with controllable microstructures can meet diversified requirements and realize promising applications. Exploring micro‐/nano‐pattern methodology offers possibilities for future techniques, however, the self‐organized growth of polymeric materials has some limitations and the development of direct and noncontact patterning processes is still challenging. In this work, the study presents a facile strategy for endowing polymers with spatially regulated microstructures by direct photo‐printing, which incorporates both advantages of typical top‐down and bottom‐up approaches. By employing the photodimerization of anthracene‐containing semi‐crystallized polymers, the gradient crosslinking results in a mismatch of thermal expansion coefficients between the crosslinked surface and the uncrosslinked bottom layer. After heating treatment, constrained by the crosslinked surface, the uncrosslinked bottom polymer of the molten state in the exposed region tends to flow and migrate toward the unexposed region, similar to a volcanic eruption, which accurately determines the height and morphology of pattern. Besides, the well‐defined patterns can controllably grow upon thermal treatment due to phase transformation and migration. The versatility of the proposed strategy not only provides a brand‐new reliable platform to pattern functional materials with photo‐regulated and reversible microstructures, but also promotes the development of smart materials that can find applications in information safety, reversible microfluidics, and electronic devices.

Microstructure evolution and mechanical properties of SiC and Nb joint brazed with AgCuTi/(Sr0.2Ba0.8)TiO3–Cu/AgCuTi composite fillers

In this study, robust silicon carbide (SiC)-niobium (Nb) joints were obtained using a composite filler consisting of a novel type of negative thermal expansion (Sr0.2Ba0.8)TiO3 particle–reinforced Cu composites (SBT-Cu) and an AgCuTi active filler. A systematic investigation was conducted to analyze the brazing temperatures and SBT-Cu thickness affect the microstructure and mechanical properties of brazed joints. The results indicated that the shear strength of SiC–Nb joints brazed with AgCuTi +80 μm SBT-Cu composite filler increased to 64 MPa at 900 °C for 15 min, which was an improvement of 146 % over the strength of joints brazed without SBT-Cu. The addition of the SBT-Cu interlayer relieved the coefficient of thermal expansion mismatch among SiC, AgCuTi and Nb. Meanwhile, the calculation results verified that the residual stresses in the joints were substantially reduced and that the coefficient of thermal expansion of the composite filler was reduced.

A comprehensive analysis of cermet design and thermal cyclic stability via elasto-viscoplastic crystal plasticity modeling

Ceramic-metal composites, or cermets, exhibit beneficial properties resulting in their use in many industrial applications. One challenge with cermets is mismatches in the coefficient of thermal expansion (CTE) values between the ceramic and metal phases that lead to residual stresses after processing, plasticity in the metal phase, internal stresses, and instability after thermal cycling. In order to make predictions of these properties to inform the design of cermets, we employ an incremental elasto-viscoplastic, self-consistent formulation to calculate the thermal, elastic, and plastic strains in two-phase polycrystalline cermet materials. This framework is extended to include temperature dependent properties, which are called implicitly within the temperature-dependent, incremental elasto-viscoplastic, self-consistent (TE-VPSC) model. Temperature-induced cooling and thermal cycling simulations are conducted using the TE-VPSC framework to study the residual stresses and plastic strains in the metal phases. Two materials are discussed in detail exhibiting stark differences based on the CTE between their ceramic and metal phases, WC/57-vol% Cu (exhibiting a pronounced CTE mismatch) and Y2O3/27-vol% Nb (exhibiting a negligible CTE mismatch). The model demonstrates high residual stresses in the Cu phase during processing and reverse plasticity leading to recovery of plastic strain during thermal cycling of the WC/Cu cermet. Moreover, the model demonstrates relatively low residual stresses and plasticity in Y2O3/Nb and a thermal stability point of 1251 °C, below which no plasticity develops in the cermet. We employ the TE-VPSC model as a design tool for cermets to systematically investigate the effects of process-induced microstructure variations (volume fraction, grain aspect ratio, and crystallographic texture are investigated) and compositional differences (19 compositions are explored) on the residual stress, degree of plasticity in the metal phase, and thermal stability point. The computational efficiency of the TE-VPSC framework makes it a desktop design tool that can be used to quantify the impact of changing composition, processing, and thermo-mechanical loading on the performance of the cermet, which can help reduce the number of time intensive and costly high temperature experiments.

First-principles study on thermal expansion of W-Re sigma and chi phases

We investigate how the Re content affects the coefficient of thermal expansion (CTE) of the non-stoichiometric W-based σ and χ phases, forming upon neutron irradiation of W, to explore and quantify its mismatch between precipitates (W-Re) and matrix (W). To this end, we have conducted first-principles calculations using two approaches: the Debye-Grüneisen (DG) model and the quasi-harmonic approximation (QHA). The two approaches yield different results: the QHA, which is deemed to be the most accurate of the two, predicts substantial changes with Re content, while the acoustic-modes based DG model does not. The CTE of the σ and χ at stable Re contents is compared to experimental values for bcc-W and bcc-W-Re containing 25 at.% Re. Taking bcc-W as a reference, we find a significant mismatch in CTE of up to 37% and 62% for σ and χ, respectively, which may contribute to thermal stress buildup in the material at elevated temperatures. The mismatch is shown to increase with the temperature and Re content for both phases. The produced data are used to fit a temperature and Re concentration-dependent analytical function of the CTE for both phases, which can be employed as input for continuum mechanical modeling.

Fabrication of penetrating pores in epitaxial Ge-on-Si through preferential etching along threading dislocations

Epitaxial Ge-on-Si possesses a high density of threading dislocations (TDs) due to the lattice mismatch and difference in thermal expansion coefficient. By employing the lattice distortion at the TDs, we demonstrate that penetrating pores along TDs can be formed in both p- and n-type heteroepitaxial Ge layers through a preferential etching. It has been found that the preferential etching at TD sites takes place in the porosification process of Ge-on-Si samples and is independent of the doping type and concentration. The penetrating pores follow the path of the TD lines and can penetrate the entire Ge layer of 1.3 μm to further porosificate the Si substrate. The effects of anodic current density and total etching duration have been thoroughly investigated on forming penetrating pores at TD sites. The dissolution mechanism in the porosification process has been revealed by dissolution valence calculation and recorded potential curves. Our findings shed light on Ge perforation in both p- and n-type Ge-on-Si and show great potential in Si-based integrated photonics and microelectronics.

Development of Ag@Si composite sinter joining with ultra-high resistance to thermal shock test for SiC power device: Experiment validation and numerical simulation

Owing to its cost-effectiveness and low coefficient of thermal expansion (CTE), micron Si is incorporated into sintered Ag matrix to develop an Ag@Si composite sintering strategy. The Si integration helps reduce cost and alleviate CTE-mismatch of Ag-sintered die attachments. An innovative Ag@Si composite sintering structure is achieved by low-temperature and pressure-less sintering process, where a possibly slight diffusion of native SiO2 on the Si surface toward Ag is indicated by TEM observation, enabling the integration of Ag and Si into one continuous network. Owing to the robust well-bonded composite sintering, the Ag@Si joining strategy provides mechanical/microstructural reliability far beyond the pure Ag sinter joining, demonstrating significant prospects in high-temperature interconnection applications. During the harsh thermal cycling (−50–250 °C), the mitigating effect of the Si addition on CTE mismatch is manifested through the substantial suppression of microstructure deterioration in Ag@Si joint that occurs in pure-Ag-sintered joint, while the shear strength retention rate is doubled. Detailed investigation into the mechanism for elevated performance was conducted by material property and Missies stress analysis. The incorporation of Si helps modify the CTE, elastic properties, and stress distribution of Ag@Si-sintered material, synergistically contributing to the satisfactory joining reliability.

Mechanically induced optical loss mechanism due to thermal expansion coefficient mismatch in micro-cavities with all-around stressor layers

Various excitation-induced loss mechanisms have been identified during the development of direct-gap semiconductor lasers. Recently, indirect-gap laser sources, particularly germanium (Ge) or GeSn based, have emerged due to silicon industry compatibility. Tensile strain is crucial for optical gain or low-threshold room-temperature operation in such media. This study investigates an excitation-induced optical loss mechanism of mechanical origin in Ge-based micro-cavities with all-around stressor layers, a popular platform for strain-engineered laser sources. Using Raman spectroscopy, photoluminescence, and simulations, we find that excitation lowers the optical gain by altering the strain profile. Heating causes Ge micro-cavities to expand within a constraining stressor layer, inducing compressive strain, which is explained by the mismatch in thermal expansion coefficients.

Exploring mounting solutions for cryogenically cooled thin crystal optics in high power density x-ray free electron lasers.

This study investigates three mounting methods-clamping, soldering, and a hybrid clamping-soldering approach-for cryogenically cooled thin diamond crystals crucial to stable operation of X-ray Free Electron Laser (XFEL) systems. While clamping methods exhibit temperature resilience and flexibility, meticulous design is required to prevent stress-induced warping and reduce thermal contact area. Soldering methods offer reliable mechanical and thermal bonding but encounter challenges due to the coefficient of thermal expansion mismatch at cryogenic temperatures. The hybrid method, integrating clamping and soldering with strain relief cuts, effectively mitigates overall distortion caused by mounting and XFEL thermal loads. These findings offer a novel mounting solution for high-performance x-ray optics in XFEL research and applications, ensuring stability and optimal functionality in cryogenic conditions.