Increasing Heat Treatment Temperature Research Articles

Effects of temperature on pure mode-I and mode-Ⅱ fracture behaviors and acoustic emission characteristics of granite using a grain-based model

To investigate the effects of thermally induced microcracks on the pure mode-I and mode-Ⅱ fracture behaviors of the granite, a Grain-based model (GBM) was used to build cracked straight-through Brazilian disc (CSTBD) granite specimens. Splitting tests were conducted on the CSTBD specimens treated at various temperatures under pure mode-I and mode-Ⅱ loadings, and the moment tensor algorithm was utilized to record the acoustic emission (AE) events generated by fracture during loading. The results indicate that thermally induced microcracks predominantly consist of intergranular and intragranular tensile cracks, with quartz phase transition significantly increasing the number of intragranular tensile cracks. With the increase in heat-treatment temperature, thermally induced microcracks gradually guide the initiation direction of load-induced cracks, making the crack propagation path more tortuous. The AE characteristics reveal that the fracture behavior of the CSTBD specimen heat-treated at 600 ℃ transitions from brittle to ductile. Furthermore, thermally induced microcracks can constrain the propagation distance of load-induced cracks, increasing the small-scale AE events and the b-value, thereby reducing the AE magnitude during failure.

Effects of heating media on microstructure and chemical composition of heat-treated Pometia pinnata

Changes of microstructure, crystallization, chemical composition, and equilibrium moisture content (EMC) of heat-treated wood (HTW) were investigated to explore the effects of heating media (saturated steam, superheated steam, air) and heat treatment (HT) temperature on HTWs. The results showed that the saturated steam induced more severe cell wall destruction than the other two media. Although the porosity slightly increased with the increasing HT temperature, superheated steam and air HT still decreased the porosity compared to that of control, whereas saturated steam HT increased the porosity. The HT increased both relative crystallinity and crystal size of HTWs. The increasing HT temperature slightly increased the relative crystallinity but decreased the crystal size. The highest crystallinity (55.0%) was observed after saturated steam HT. Leaching led to the increase of crystal size of HTW treated in saturated steam (about 0.15 nm), while those treated in unsaturated steam and air decreased. The increase in relative amount of lignin and cellulose due to the hemicellulose degradation were the main chemical changes of HTWs. Further lignin condensation reaction only occurred after saturated steam HT. Although saturated steam HT induced increased porosity, its lowest EMC (5.91%) indicated the decrease of hydroxyl groups.

Influence of the Structure of Hydrothermal-Synthesized TiO2 Nanowires Formed by Annealing on the Photocatalytic Reduction of CO2 in H2O Vapor.

The present study investigates the photocatalytic properties of hydrothermally synthesized TiO2 nanowires (NWs) for CO2 reduction in H2O vapor. It has been demonstrated that TiO2 NWs, thermally treated at 500-700 °C, demonstrate an almost tenfold higher yield of products compared to the known commercial powder TiO2 P25. It has been found that the best material is a combination of anatase, TiO2-B and rutile. The product yield increases with increasing heat treatment temperature of TiO2 NWs. This is associated with an increase in the degree of crystallinity of the material. It is shown that the best product yield of the CO2 reduction in H2O vapor is achieved when the TiO2 NW photocatalyst is heated to 100 °C.

Comparative study of microstructure and mechanical properties of cold rolled and annealed CoCrFeNi-MEA and CoCrFeNiMn-HEA fabricated by laser energy deposition

Equi-atomic quaternary CoCrFeNi Medium-entropy alloy (MEA) and quinary CoCrFeNiMn high-entropy alloy (HEA) are fabricated by laser energy deposition, followed by 5-pass cold rolling to total reduction of 70 % and annealing at temperatures of 600–1000 °C for 1 h. CoCrFeNi-MEA is severely cracked while CoCrFeNiMn- HEA is slightly cracked after cold rolling. Hardness of as deposited and fully recrystallized (heat treating temperature at 800–1000 °C) CoCrFeNi-MEAs are slightly higher than those of CoCrFeNiMn- HEAs, due to the larger atomic size misfit and lattice strain in CoCrFeNi-MEA than in CoCrFeNiMn-HEA. However, the higher microhardness of CoCrFeNiMn-HEAas-rolled than CoCrFeNi-MEAas-rolled is associated with the higher strain state in CoCrFeNiMn-HEAas-rolled than in CoCrFeNi-MEAas-rolled. With the increase of heat-treating temperature, microhardness of CoCrFeNi-MEA increases first and then decreases due to the precipitation hardening effect of Cr-rich (B2) particles in CoCrFeNi-MEAR-600. Microhardness of CoCrFeNiMn-HEA decreases with the increase of annealing temperature because of the weaker precipitation hardening effect of MnNi phase (L10) and Cr-rich particles (BCC) after annealing at 600 ℃ and higher temperatures. CoCrFeNi-MEAR-700 is much harder than CoCrFeNiMn-HEAR-700 because CoCrFeNi-MEAR-700 is partially recrystallized and CoCrFeNiMn-HEAR-700 is fully recrystallized. Strength behavior of the two alloys is consistent with microhardness behavior. {100}<110> texture component is acquired in both CoCrFeNi-MEAas-rolled and CoCrFeNiMn-HEAas-rolled. <111>//ND texture is observed in both alloys after annealing at 600 ℃. Orientation of recrystallized grains is random in both alloys. Size of recrystallized grains in CoCrFeNiMn-HEA is slightly larger than those in CoCrFeNi-MEA since homologous temperature (T/Tm) of CoCrFeNiMn-HEA is slightly higher than that of CoCrFeNi-MEA.

Effect of Cooling Method on Physical and Mechanical Properties of PVA Fiber-Reinforced High-Strength Concrete Exposed to High Temperature.

High-strength concrete (HSC) boasts excellent compressive strength and durability, making it a popular choice in various engineering applications. However, under the impact of high temperatures, HSC tends to crack easily, so it is combined with polyvinyl alcohol fiber (PVA fiber) to explore its engineering application prospect. This paper investigated the physical and mechanical characteristics of HSC reinforced with PVA fibers subjected to different heating temperatures and cooling techniques. The experimental results reveal a correlation between rising temperatures and observable changes in the specimens: a progressively lighter surface hue, an augmented frequency of cracking, and a considerable escalation in the mass loss rate, particularly after the temperature exceeds 400 °C. Regarding mechanical properties, the dynamic elastic modulus and compressive and flexural strength all decrease as the heating temperature increases. As the amount of PVA fiber rises while maintaining a steady temperature, these measurements initially show an increase followed by a decrease. The fiber contents yielding the best compressive and flexural strength are 0.2% and 0.3%, in that order. Considering the influence of cooling methods, water spray cooling has a greater impact on physical and mechanical properties than natural cooling. Furthermore, SEM was employed to scrutinize the microstructure of HSC, enhancing comprehension of the alterations in its physical and mechanical characteristics. The findings of this research offer significant information regarding the high-temperature behavior of HSC, serving as a valuable resource for guiding the design, building, and upkeep of structures that incorporate HSC. Additionally, this study will aid in advancing the progress and utilization of HSC technology.

Experimentation and simulation of gas flow field distribution during the growth of carbon nanotubes in a horizontal reactor

Carbon nanotubes (CNTs) were grown in a horizontal reactor by chemical vapor deposition, and it was found in the experiments that different heating temperatures and the position of the porcelain boat affect the morphology and yield of CNTs. Computational fluid dynamics (CFD) software is used to simulate the gas flow field distribution in the horizontal reactor under different operating parameters, and the results revealed that the gas flow in the horizontal reactor was advancing with vortex, and this gas circulation is induced by the difference in density due to the existence of temperature difference between the gas streams. As the heating temperature and nitrogen gas velocity increase, this vortex distorts the laminar flow, which in turn weakens the growth of CNTs.

Effect of different temperature–time combinations on the quality and protein digestive properties of stewed beef tendons

This study investigated the effects of sous vide cooking and traditional high-temperature cooking on the texture, microstructure, protein structure and digestive properties of home made beef tendon using transmission electron microscopy, in vitro digestion and peptidomics. The adverse effects of heating on the muscle fiber structure and protein conformation of beef tendon gradually expanded with increasing temperature. In general, the degree of muscle fiber contraction, protein denaturation, and protein aggregation increases with temperature and time, with a concomitant decrease in protease action. The extent of protein digestion, and the yield of small fragments such as amino acids also decreased with increasing heating temperature and time. However, the solubilization of collagen makes the beef collagen more digestible after heating at 80°C, which indirectly leads to higher digestibility at 80°C. The combined peptide release and bioactive peptide results showed that the beef tendon heated at 60°C for 8 h produced the most peptides after digestion, and also produced four specific bioactive peptides, which were advantageous in terms of the number of digested products and bioactivity. The higher proportion of antioxidant amino acids in the product also gave the tendon heated at 60°C for 8 h a greater potential antioxidant capacity. As a result, beef tendon heated at 60°C for 8 h is more favorable for human digestion. This work may provide guidance for home cooking and dietary health.

Effect of heat treatment conditions on the phase transformation characteristics of nitinol

Nitinol is the most widely used shape memory alloy in medical applications. In this study, the effect of different heat treatment conditions on the phase transformation characteristics of medical-grade nitinol was investigated. Nickel-rich nitinol wires containing 50.6% nickel with a diameter of 120 μm were used in the experimental studies. The nitinol wires were heat treated for 10 minutes at heat treatment temperatures between 540 and 570 °C. Then, nitinol wires were heat treated at a heat treatment temperature of 550 °C between 8 and 14 minutes. The austenitic and martensitic transition temperatures of these samples were measured using differential scanning calorimetry (DSC). In the experiments with 10 minutes of heat treatment time, transition temperatures decreased, and hysteresis increased with the increase in heat treatment temperature. This is related to the amount of precipitates in the structure. In the experiments carried out at 550 °C, transition temperatures decreased, and hysteresis increased with increasing heat treatment time. Experimental studies showed that the austenite finish (Af) temperature of all nitinol wire samples was below 37 °C, and they will exhibit superelasticity in the human body.

Numerical investigation of the transient fluid flow and heat transfer behavior in self-driven natural circulation cooling loop

An innovative open natural circulation system is proposed in this work, which utilizes the difference of the heat flux loaded on different parts of the pipe to form a self-circulation flow of working fluid. Via CFD simulation established by embedding self-programmed code into commercial software, the transient performance of a three-dimensional natural circulation loop is studied. The results indicate that: applying uniform heat flux on the wall of the loop, the fluid flow state successively experiences three stages, i.e., liquid expansion, partial circulation, and phase change, and finally a vapor plunger blocks the pipe, leading to local heat transfer deterioration and temperature increase; applying non-uniform heat flux, the fluid can be driven to form self-circulation flow, which can not only cool the structure via convection, but also prevent bubbles from accumulating, stabilizing the maximum temperature of the system around the boiling point; further for the loop with a more complex configuration, the self-circulation can be also started but with different start modes. Therefore, the new natural circulation system can achieve effective and adaptive cooling according to the external thermal environment, avoid fluctuation and vapor block phenomenon caused by violent phase change, and reduce the driving equipment and control unit. This work provides a reference for the design of the natural circulation system applied in a non-uniform heating environment. Through transient numerical simulation of the start-up stage, the fluid flow, phase change, and heat transfer characteristics in the natural circulation loop are studied, and the start mode and mechanism are analyzed.

An Experimental Study on the Influence of Different Cooling Methods on the Mechanical Properties of PVA Fiber-Reinforced High-Strength Concrete after High-Temperature Action.

High-strength concrete (HSC) has a high compressive strength, high density, excellent durability, and seepage resistance, but its deformation ability is weak. Adding fibers can improve the physical and mechanical properties of HSC. Additionally, the HSC structure may face the threat of fire. In the process of fire extinguishing, the damage mechanism of high-temperature-resistant concrete is complicated due to the different contact conditions with water at different locations. Hence, it is essential to conduct pertinent research on the behavior of fiber-reinforced HSC with different cooling methods after high-temperature action. In this paper, polyvinyl alcohol fiber (PVA fiber) was selected to be added into the HSC to carry out high-temperature experimental research, so as to explore the apparent changes, failure pattern, and mass loss rate of the fiber-reinforced HSC using different cooling methods and analyze the influence of its residual compressive strength and flexural strength. The test results suggest that, with the increase in heating temperature, the color of the specimen's surface transitions from dark blue-gray to white, and the quantity of surface cracks on the specimen gradually rises. The mechanical strength gradually decreases as the heating temperature increases. At a consistent heating temperature, the mechanical strength initially rises, and then falls with an increase in fiber content. The maximum compressive strength and flexural strength were achieved at PVA fiber contents of 0.2% and 0.3%, respectively. For different temperatures and fiber contents, the mechanical strength after natural cooling is generally higher than that after immersion cooling. In addition, X-ray polycrystalline diffractometry (XRD) and scanning electron microscopy (SEM) tests were conducted to analyze the compositional alterations and microstructure of the fiber-reinforced HSC following high-temperature exposure, accompanied by an explanation of the factors influencing the alterations in the physical and mechanical properties. Therefore, the findings of this study can serve as a valuable reference for the utilization of HSC in engineering structures and contribute to the advancement of HSC technology.

Austenite Growth Behavior and Prediction Modeling of Ti Microalloyed Steel.

Previous studies on the austenite grain growth were mostly based on a fixed temperature, and the relationship between the austenite grain and austenitizing parameters was fitted according to the results. However, there is a lack of quantitative research on the austenite grain growth during the heating process. In the present work, based on the diffusion principle of the controlled Ti microalloying element, the diffusion process of carbonitrides containing Ti during the heating process was analyzed. Combined with the precipitation model and the austenite growth model, the prediction model of austenite grain growth of Ti microalloyed steel during different heat treatment processes was established. The austenite grain size versus the temperature at four different heating rates of 0.5, 1, 10, 100 °C/s was calculated. The grain growth behavior of austenite during the heating process of Ti microalloyed steel was studied by optical microscope, scanning electron microscope and transmission electron microscope. The experimental data of the austenite grain size was in good agreement with the calculation by the proposed model, which provides a new idea for the prediction of austenite grain size in non-equilibrium state during the heating process. In addition, for Ti-containing microalloyed steels, the austenite grain size increased with the increasing heating temperature, while it changed little by further prolonging isothermal time after certain heating time, which was related to the equilibrium degree of the precipitation and the dissolution of Ti element. The austenite grain coarsening temperature of the tested Ti microalloyed steel was estimated within 1100~1200 °C.

Radiofrequency pasteurization of Aspergillus flavus ATCC 28539 spores at cellular and molecular levels

Radio frequency (RF) heating has been used to study pasteurization technology, but its mechanism has not been thoroughly studied, especially for fungi. In this paper, pasteurization processes and potential bactericidal mechanisms of Aspergillus flavus spore using RF was investigated. The best heating and pasteurization efficiency were achieved at (Electrode gap 130 mm, conductivity of spore suspension 0.1 S/m, volume of spore suspension 40 mL). At the cellular level, with the increase of RF heating temperature to 80 °C, the number of surviving cells decreased dramatically, the degree of cellular damage deepened through observation, the absorbance values of nucleic acid and protein increased to 0.468 ± 0.016 and 0.526 ± 0.023 respectively, the conductivity reached 99.0 ± 0.5%, the fluorescence intensity of reactive oxygen content increased to 51.6 ± 1.6 AU, while adenosine triphosphate (ATP) concentration reduced to 0.57 ± 0.07 mM. At the molecular level, transcriptomics analysis showed that the number of differentially expressed genes (DEGs) increased with the temperature increased. Gene ontology (GO) annotation analysis showed that DEGs mainly existed in the molecular function. This study investigated the potential bactericidal mechanism of A. flavus using RF, provided some theoretical basis for the research of the pasteurization of fungi.

In situ DRIFTS analysis of the evolution of surface species over Li6PS5Cl solid state electrolyte during moisture-induced degradation and during heat treatment

Sulfide SSEs (solid-state electrolytes) with high ionic conductivity are attractive for developing high-safety all-solid-state batteries (ASSBs). However, the poor chemical stability of sulfide SSEs toward moisture is a significant problem. Though the decomposition products when exposed to moisture and a possible property recovery by heat treatment are reported, the evolution of surface species in related to moisture exposure and to heat treatment is not clearly identified. This study applies in situ DRIFTS (diffuse reflectance infrared Fourier-transformed spectroscopy) analysis to examine the evolution of the surface species over pristine Li6PS5Cl (LPSC), during moisture exposure, and during heat treatment, complementary with tools like XRD, Raman, etc. The observed surface impurities over pristine LPSC include LiCl·H2O, LiOH·H2O, S3P-SH, PS4-xOx, SOx and carbonate species. Moisture exposure leads to increasing accumulation of these species over LPSC and evolving hydrogen sulfide. A stepwise heat treatment up to 480 °C illustrates the sequential removal of hydrated water, the decomposition of carbonate, LiOH, and PS4-xOx, leaving species like LiCl, Li2O, and PO4 on the surface. The EIS results shows a gradual increase in the ionic conductivity of LPSC with increasing heating temperature, mainly owing to the decreasing surface layer impedance. This strongly suggests that the surface species govern the properties of LPSC. When using the pristine LPSC after heat treatment at 480 °C, the Li||pristine LPSCHT||Li symmetric cell demonstrates a decreased polarization and a much-enhanced cycle stability comparing to the Li||pristine LPSC||Li symmetric cell.

Effect of deep cryogenic treatment on improving the high-temperature impact resistance of Al–Zn–Mg–Cu alloy

The aging Al–Zn–Mg–Cu alloy exhibits a significant decrease in performance after undergoing thermal shock. In order to improve the resistance of this type of alloy to thermal shocks, the influence of deep cryogenic treatment (DCT) on the high temperature mechanical properties and microstructure of thermal shocked Al–Zn–Mg–Cu alloy is investigated in this paper. It was found that the mechanical properties of Al–Zn–Mg–Cu alloys decrease significantly with the increase of electric heating temperature. The deep cryogenic treatment reduced the grain size of Al–Zn–Mg–Cu alloy, increased the density of the precipitates, and also inhibited the coarsening of the precipitates. Therefore, the deep cryogenic treatment can slow down the weakening effect of Al–Zn–Mg–Cu alloy at high temperatures.

Analysis of the influence of heating temperature on the convective drying process

The study examines the influence of heating temperature during the convective drying of fruits on the mass fraction of moisture in the finished product. Convective drying is a promising method for preserving products, allowing the production of dried fruits that can provide essential nutrients year-round. The experiments detailed in this article aim to establish optimal fruit drying modes. Standard methods were used to analyze the experiments according to regulatory documents in force in Kazakhstan. The authors proposed diagrams of convective drying of the fruits in the south of Kazakhstan. According to the constructed schemes, it can be seen that the heating temperature during the drying process affects the final product. According to the analysis, an increase in heating temperature results in a decreased drying time. At the specified time, the highest conversion rate of the relative mass of the dried product is detected. Additionally, it was obtained that the temperature, size, and structure of fresh raw materials affect the period of maximum moisture volatilization rate. The authors carried out a sensory evaluation of the main quality indicators: taste, color, odor and consistency. The optimal characteristics of the indicators were determined. They were extracted at a heating temperature of 50 ....65 °C. Numerous experiments have shown that it is necessary to offer such convective drying parameters. Convective drying temperature for apples is 50-55 °C, for apricots - 55-65 °C, for prune plums - 60-65 °C. Such results will be useful in the technology of fruit and vegetable processing.

The composition and flavor change mechanism of membrane-filtered sugarcane syrup during the acid hydrolysis process based on 1H NMR and GC–IMS

Nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to comprehensively characterize both non-volatile and volatile components present in membrane-filtrated sugarcane syrup (MS). A total of 19 non-volatile compounds and 65 volatile compounds were successfully identified within the MS sample. Among the volatile compounds, 12 were determined to be key aroma contributors based on their Relative Odor Activity Values (ROAV). Our investigation elucidated that hydrolysis and Maillard reactions serve as the primary pathways during acid hydrolysis, with reaction kinetics strengthened by increasing heating temperature and citric acid concentration, thereby enhancing the caramel and roasted aromas of MS. These findings not only contribute to a deeper understanding of the composition of sugarcane syrup but also offer valuable insights into flavor characterization and quality control within the sugarcane industry. Furthermore, this research lays a foundation for future studies aimed at optimizing processing techniques to enhance syrup flavor and overall product quality.

Influence of Cyclic Heat Treatment Temperature on Microstructure and Mechanical Properties of 18Ni(C250) Maraging Steel.

Cyclic heat treatment is an effective approach for enhancing the mechanical properties of 18Ni(C250) maraging steel, and the selection of cyclic heat treatment temperature is a key factor. In this study, a cyclic heat treatment process with a two-step solution treatment is employed to investigate the influence of cyclic heat treatment temperature, specifically the first solution treatment temperature (920 °C, 950 °C, and 980 °C), on the microstructure and mechanical properties of 18Ni(C250) maraging steel. The results indicate that with an increase in the cyclic heat treatment temperature, the average grain size of the 18Ni(C250) maraging steel decreases initially and then increases. When the cyclic heat treatment temperature reaches 950 °C, the grain size is at its minimum, exhibiting optimal grain uniformity. Additionally, the increase in cyclic heat treatment temperature results in a reduction in the size of martensitic lath with the same orientation inside the grains, along with an increase in the relative quantity of low-angle grain boundaries. Furthermore, the volume fraction and size of retained austenite show a monotonous increase with the rise in the temperature of the cyclic heat treatment, and the rate of increase becomes notably larger when the temperature is raised from 950 °C to 980 °C. Based on the observed microstructural changes, the variation in the mechanical properties of the 18Ni(C250) maraging steel was analyzed. Specifically, as the cyclic heat treatment temperature increases, the tensile strength of the 18Ni(C250) maraging steel initially increases and then stabilizes, while the elongation and fracture toughness exhibit a monotonic increase.

The radiation protection and high temperature performance of serpentine-magnetite mixed concrete

In this paper, the high density of magnetite and the high crystal water content of serpentine are used to configure concrete with high temperature resistance, gamma ray shielding and neutron shielding properties, and adjust the proportion of magnetite and serpentine to prepare five different proportions of serpentine magnetite mixed concrete, then studies the compressive strength of mixed concrete with different proportions; splitting tensile strength; quality loss; hydrogen content; γ radiation shielding performance; ultrasonic pulse velocity. The results show that the compressive strength of the mixed concrete increases from 31.5 MPa to 40 MPa, the linear attenuation coefficient of γ-ray increases from 0.17 to 0.259, and the hydrogen content decreases from 1.5989 % to 0.3778 % with the increase of magnetite content in the aggregate. Under different mix ratios, with the increase of heating temperature, various properties of mixed concrete gradually decrease, the minimum ultrasonic wave speed of concrete will drop to 24.1 % of the original wave speed, and the minimum compressive strength will drop to 25.1 % of the compressive strength at normal temperature. However, before the heating temperature of 600°C, the compressive strength can still be maintained at more than 75 % of the normal temperature compressive strength.The concrete above has good thermal stability.

Research on uniaxial compression performance and constitutive relationship of RBP-UHPC after high temperature

Abstract This study examines the impact of the recycled brick powder (RBP) replacement rate, especially at elevated temperatures on RBP-ultra-high-performance concrete (UHPC) properties such as the stress–strain curve, Poisson’s ratio, elastic modulus, and axial compressive strength through uniaxial compression experiments. The results show that with the increase of heating temperature, the axial compressive strength of the specimen increases first and then decreases under natural cooling (NC). In contrast, Poisson’s ratio shows opposite values. The peak strain continues to increase, and the initial elastic modulus and peak secant modulus continue to decrease. Compared with NC, the axial compressive strength of the specimens under water cooling has been reduced, the peak strain is generally larger, the initial elastic modulus and the peak secant modulus are smaller, and the incorporation of RBP also has a certain effect on the mechanical properties. Through regression analysis, an equation is established to calculate the axial compressive strength of RBP-UHPC with temperature, accounting for variables such as temperature, RBP replacement rate, and cooling method. Furthermore, based on the results of axial compression experiments, a constitutive equation for axial compression in RBP-UHPC after exposure to high temperatures is proposed. Overall, the theoretical curve closely aligns with the experimental curve, verifying its accuracy.

Influence of heat treatment on nanomechanical properties of Ni-based superalloy 625 fabricated by ultrasound-assisted wire arc additive manufacturing

This investigation focused on the effect of heat treatment (HT) temperature on microstructure and nanomechanical properties of Ni-based superalloy 625 fabricated by ultrasound-assisted wire arc additive manufacturing (UA-WAAM). The homogenization of the microstructure was significantly improved due to the HT helping unwanted secondary phases to dissolve back into the matrix. The nanoindentation results showed that with an increase in HT temperature, the average nano-hardness decreased from 2.13 ± 0.20 GPa to 1.39 ± 0.15 GPa, while the average creep displacement increased from 189.12 ± 33.26 nm to 634.79 ± 48.20 nm.