Steady-state Stage Research Articles

АНАЛИЗ ВЛИЯНИЯ КОНСТРУКТИВНЫХ ПАРАМЕТРОВ НА МАНЕВРЕННОСТЬ ТРАКТОРА СО ВСЕМИ УПРАВЛЯЕМЫМИ КОЛЕСАМИ

The results of a theoretical analysis are presented to assess the influence of the longitudinal base and track of a tractor with all steerable wheels on its basic geometric and kinematic characteristics in curved motion, characterizing its maneuverability. The maximum abscissa and ordinate of the trajectory of the entrance to the turn and the minimum theoretical radius of the steady-state stage of a circular loop-free turn are taken as estimated indicators. A comparison is given with the calculation results obtained in the study of a tractor with front steerable wheels under identical design parameters and operating conditions. To determine the necessary desired parameters describing the trajectory of the curved movement of the tractor, parametric equations are obtained. Analysis of the calculation results showed that with an alternate increase in the length of the longitudinal base from 2.2 m to 3.0 m and the track width from 1.2 m to 2.2 m, with the remaining unchanged design and operational characteristics, the minimum radius increases, respectively, by 18.5% and 16.3%, and the maximum ordinate of the trajectory of entry into the turn – by 3.9% and 16.6 %, while the maximum abscissa of this section of the trajectory decreases by 20.4 % and 40.4%. A comparison of the turning method, which is the subject of research in this paper, with the method of turning the front steerable wheels, all other things being equal, showed the effectiveness of the first of them. An increase in the maximum abscissa by 1.75 times was revealed, but a decrease in the maximum ordinate by 1.05 times and the minimum turning radius by 1.69 times. This gives reason to talk about the best maneuverability of a tractor with all steerable wheels.

Experimental study of the evaporation characteristics of unsymmetrical dimethylhydrazine in a sub-supercritical environment

In this study, the temperature–pressure separation technique was used to successfully obtain the process of the unsymmetrical dimethylhydrazine droplet diameter variation with time during evaporation in subcritical, supercritical, and far-supercritical environments at temperatures and pressures of 473–773 K and 1–9 MPa, respectively. The results show that unsymmetrical dimethylhydrazine droplet evaporation has two characteristic stages, transient heating and steady-state evaporation, under low-pressure and low-temperature environments; the steady-state evaporation stage influences droplet evaporation life more than the transient heating stage. Under high-pressure and high-temperature environments, droplet evaporation shows only a single feature of steady-state evaporation, and the droplet expansion process in the transient heating stage disappears. The normalized droplet lifetime decreased exponentially with temperature and decreased linearly and monotonically with pressure. The evaporation rate constant increases linearly and monotonically with temperature and exponentially with pressure.

Initial Vacancy-Dependent High-Temperature Creep Behavior of Nanocrystalline Ni by Molecular Dynamics Simulation

Nanocrystalline metals possessing excellent mechanical strength have great potential to replace traditional metal materials as structural materials, but their poor resistance to creep deformation seriously restricts their engineering applications at high temperatures. The high-temperature creep behavior of nanocrystalline Ni with different volume fractions of initial vacancies ranging from 0% to 10% was studied systematically by molecular dynamics simulation in this study. The results showed that the steady-state creep displacement first increased and then decreased with increasing initial vacancy concentration, reaching the maximum when the initial vacancy concentration was 6%. The microstructural characteristics, such as quantity increment and distribution of the vacancies, the number and types of dislocations, and shear strain distribution during creeping, were analyzed in detail. The deformation-induced vacancies formed at the grain boundary (GB) in the initial creep stage, and their variation trend with the initial vacancy concentration was consistent with that of the creep displacement, indicating that the initial vacancy-dependent high-temperature creep behavior of nanocrystalline Ni was mainly determined by the rapidly increasing number of vacancies at the GB in the initial creep stage. Afterwards, the deformation-induced, vacancy-assisted 1/6{112} Shockley partial dislocation activities dominated the creep deformation of nanocrystalline Ni in the steady-state creep stage. The results can provide theoretical support for expanding the application of nanocrystalline metals from the perspective of crystal defect engineering.

Addressing challenges in high-temperature oxidation of ultra-supercritical boiler tubes via FeCoNiCrMo high-entropy alloy coatings

The engineering realm confronts formidable challenges in combating the persistent issue of high-temperature oxidation in ultra-supercritical coal-fired boiler tubes. This study is dedicated to tackling these challenges by employing high-velocity oxy-fuel spraying (HVOF) and high-frequency induction remelting techniques. Our primary objective is to establish a metallurgical bond between self-fusing FeCoNiCrMo high-entropy alloy (HEA) powder and the conventional 15CrMo boiler steel tube surfaces, all within ambient atmospheric conditions. Our investigation reveals two distinct stages of oxidation for the HEA coating when exposed to a 900 °C air environment. Initially, there is a rapid oxidation stage driven by interfacial reactions, followed by a steady-state slow oxidation stage influenced by ion diffusion. The presence of a dense Cr2O3 layer plays a pivotal role in reducing the oxidation rate significantly, thereby imparting exceptional high-temperature oxidation resistance to the FeCoNiCrMo HEA coating. Notably, during the steady-state stage, the oxidation rate is two orders of magnitude lower than observed in Ni-based superalloys. Minimal phase transformations or transitional layers at the interface underscore superb interface bonding at 900 °C. These findings provide a promising avenue for the cost-effective fabrication of highly oxidation-resistant ultra-supercritical boiler tubes. This advancement contributes significantly to the progress of engineering applications.

Electromechanical coupling characteristics analysis of vertical stirred mill based on ECS-MBD-DEM

This paper focuses on the start-up and steady-state operation stages of a vertical stirred mill, and the electromechanical coupling characteristics are thoroughly investigated based on the ECS-MBD-DEM coupling method. Firstly, according to the driving and working principles of the vertical stirred mill, the electrical control system (ECS) and multibody dynamics (MBD) model of the vertical stirred mill are separately established. Subsequently, a discrete element method (DEM) model is developed for the grinding media inside the mill. On this basis, the ECS-MBD-DEM coupling model of the vertical stirred mill is constructed, and its feasibility is validated through experiments. Then, the pitch, screw diameter, grinding media filling, and mill rotation speed of the helical agitator are considered as influential factors, with average value and coefficient of variation used as evaluation indicators for the level and fluctuation of changes. The load torque and current amplitude during the start-up and steady-state stages of the vertical stirred mill are analysed separately based on the ECS-MBD-DEM coupling method. The results indicate that the pitch, screw diameter, and grinding media filling have a significant effect on the average value of load torque. The screw diameter, grinding media filling, and mill rotation speed significantly influence the coefficient of variation of the load torque. The mill speed has a significant effect on the average value and coefficient of variation of the current amplitude. Finally, the cumulative volume velocity difference is proposed as an evaluation indicator for the grinding efficiency in the annular region, and the impact of influential factors on it is discussed, the results show that the grinding media filling and mill speed have a significant impact on the cumulative volume velocity difference.

Shear creep characteristics and creep constitutive model of bolted rock joints

The shear creep behavior of bolted rock joints is closely related to the long-term stability of bolt-reinforced high slopes and underground caverns. To investigate the controlling effect of bolts on rock joint shear creep, limestone samples from the Wudongde dam site area in southwest China were collected and processed, and multistep shear creep tests were conducted on both bolted an unbolted rock joints. The results show that the shear creep of bolted rock joints includes the instantaneous strain stage, transient creep stage and steady-state creep stage, yet the accelerating creep typically occurs instantaneously and is unobservable. By comparing the shear creep process of bolted and unbolted rock joints, it is observed that the presence of bolts decelerates the deterioration of joint surfaces, resulting in a shorter duration of transient creep and lower creep rate. Furthermore, the bolt alters the creep failure mode of the rock joint from brittle failure to plastic failure. Based on experimental results, the reinforcement effect of the bolt through joint creep is analyzed, and the stress evolution during creep is divided into three stages, i.e., the stress-compatibility stage, the stress-compensation stage, and the stress-limitation stage. We summarize how the bolt compensates for stress loss caused by joint surface deterioration through increased shear and axial forces, thereby reducing the creep rate and creep deformation of the rock joint. Based on the stress compensation mechanism of the bolt, a B-Q-N (Burgers-shear force Qo-axial force No) creep constitutive model for bolted rock joints is proposed. When the creep behavior of the unbolted rock joint and the anchorage parameters are known, the B-Q-N model can describe the shear creep behavior of bolted rock joints without experimental data for parameter identification, as well verified by our tests.

On the effect of tempering temperature on the long-term creep behavior of a 10% Cr steel with low nitrogen and high boron contents

The effect of a decrease in the tempering temperature from 770 to 750 °C on the long-term creep behavior of a 10% Cr martensitic steel with 0.008 wt % B and 0.003 wt % N was studied. The evolution of microstructure and precipitation distribution during creep was examined using the interrupted tests under an applied stress of 120 MPa at 650 °C. It was found that a higher dislocation density, a finer lath structure and finer carbides after tempering at 750 °C did not provide higher long-term creep strength than after tempering at 770 °C. The creep rupture time was about 30% shorter. Effect of changes in the dislocation density, lath width, sizes of M23C6 carbides and Laves phase particles, and precipitation of V-rich MX phase on the strengthening contribution at the onset of creep and at the transient, apparent steady-state and tertiary stages was analyzed. The higher dislocation density formed by the tempering at a lower temperature provided a higher climb velocity at the transient creep stage. The higher driving force for recovery was not fully compensated by the higher strength exerted by smaller M23C6 carbides. This led to faster annihilation of the lath boundaries and a decrease in internal stress and, consequently, to an order of magnitude higher minimum creep rate of the steel after tempering at 750 °C as compared to tempering at 770 °C.

Compressive creep behavior of selective electron beam melted high Nb containing TiAl alloy

In this study, the compressive creep behavior of Ti–45Al–8Nb alloy fabricated by selective electron beam melting technology at 800 °C and 850 °C was investigated. This alloy is mainly composed of equiaxed γ grains, and minor α2 and B2 grains. Creep results show that compressive creep behavior of this alloy is dependent on temperature, which is manifested in the significant increase of creep strain and creep rate with the increase of temperature. Through a multi-step creep test, the stress exponent n (2.65 at 800 °C and 3.65 at 850 °C) and activation volume V* (36.49 b3 at 800 °C and 53.51 b3 at 850 °C) were measured. Combined with kinetic analysis based on n and V* and TEM observation, compressive creep deformation of this alloy at 800 °C and 850 °C is dominated by dislocation motion, including dislocation slip and climb. Additionally, mechanical twinning also plays an important role in creep deformation. Driven by dislocation pile-ups or mechanical twins, discontinuous dynamic recrystallization (DDRX) occurs during creep. The degree of DDRX at 850 °C is greater. Sufficient DDRX greatly softens the alloy and accelerates creep rate, resulting in no steady-state creep stage at 850 °C.

Study on creep characteristics and component model of saline soil in hexi corridor

Accurate mastery of the creep characteristics of unsaturated saline soil is extremely important for the long-term stability and safe operation of all types of buildings. In this paper, the research object focused on the saline soil of the Zhangye area, Hexi corridor. The indoor triaxial CU creep test was carried out by means of graded loading to study the creep characteristics of saline soil under different salt content and loading stress. The Merchant and Burgers models were used to predict the creep behavior of the saline soils, and the predicted results were compared with the experimental values. The results showed that the triaxial creep curve of saline soil developed in stage III. Namely, transient creep stage, deceleration creep stage and steady-state creep stage. The creep deformation increases with the increase of salt content and loading stress. The stress–strain isochronous curve has non-linear growth, and the cluster of curves develops from dense to sparse after increasing to long-term strength (100∼150 kPa). The parameters of the Merchant and Burgers model vary with salt content and loading stress, and the creep curve predicted by the Burgers model is closer to the test value.

Creep damage and crack propagation behavior of printed circuit heat exchanger manufactured by diffusion welding: from material to structure

The printed circuit heat exchanger (PCHE) is extensively used in several applications due to exceptional compactness and heat transfer efficiency. However, the dominant failure mode of PCHE is creep fracture in its diffusion welding joints. Therefore, an accurate prediction of the creep crack propagation behavior for diffusion welding joints is essential for assessing the life of PCHE. In this paper, based on the research route from material to structure, the creep properties of 316L stainless steel base metal and its diffusion welding joint are firstly measured. On this basis, a constitutive model incorporating a time-hardening term for describing the creep damage is established. Furthermore, the creep damage and service life of the PCHE structure under working conditions (600 °C, 20 MPa) are analyzed, along with the effects of structure factors on the creep crack propagation behavior. The results show that the initial decelerating stage and the steady state stage play a dominate role in the creep curve of the diffusion welding joint, differing from the base metal's creep curve. Besides, the creep rate of the joint is approximately 30 times that of the base metal. The established creep damage constitutive model effectively characterizes the creep crack propagation behavior of diffusion welding joints. The maximum creep strain occurs at the weld metal and continuous operation for 100,000 h can be achieved at the designed working condition (600 °C, 20 MPa). For the purpose of lifetime extension by restraining the creep crack, it is recommended to increase the spacing and fillet radius while reducing the diameter during design process.

Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature

Ten percent Cr steels are considered to be prospective materials for the production of pipes, tubes, and blades in coal-fired power plants, which are able to operate within ultra-supercritical steam parameters. The microstructural evolution of a Re-containing 10% Cr-3Co-3W steel with low N and high B content during creep was investigated at different strains at 923 K and under an applied stress of 120 MPa using TEM and EBSD analyses. The studied steel had been previously normalized at 1323 K and tempered at 1043 K for 3 h. In the initial state, the tempered martensite lath structure with high dislocation density was stabilized by M23C6 carbides, NbX carbonitrides, and M6C carbides. At the end of the primary creep stage, the main microstructural change was found to be the precipitation of the fine Laves phase particles along the boundaries of the prior austenite grains, packets, blocks, and martensitic laths. The remarkable microstructural degradation processes, such as the significant growth of martensitic laths, the reduction in dislocation density within the lath interiors, and the growth of the grain boundary Laves phase particles, occurred during the steady-state and tertiary creep stages. Moreover, during the steady-state creep stage, the precipitation of the V-rich phase was revealed. Softening was in accordance with the dramatic reduction in hardness during the transition from the primary creep stage to the steady-state creep stage. The reasons for the softening were considered to be due to the change in the strengthening mechanisms and the interactions of the grain boundary M23C6 carbides and Laves phase with the low-angle boundaries of the martensitic laths and free dislocations.

Compressive creep behavior of high Nb containing TiAl alloy: Dynamic recrystallization and phase transformation

In this work, compressive creep behavior of Ti-43Al-6Nb-1Cr-1.5V alloy fabricated by vacuum induction skull melting technology was investigated at 800-950 °C. The results show that compressive creep behavior of this alloy strongly depends on temperature. At 800 °C and 850 °C, this alloy exhibits conventional three-stage creep characteristics with a well-defined steady-state creep stage, and creep strain is small. However, at 900 °C and 950 °C, this alloy exhibits unconventional creep characteristics, and creep strain increases sharply. Microstructure observation proves that this is mainly due to the occurrence of dynamic recrystallization (DRX). During creep, continuous dynamic recrystallization and discontinuous dynamic recrystallization appear simultaneously, but the latter is more significant. At 800 °C and 850 °C, creep deformation mainly depends on dislocation motion, while at 900 °C and 950 °C, DRX also greatly contributes to creep deformation. During creep, recrystallized grains preferentially form at β-segregation and α-segregation, and rising temperature from 850 °C to 900 °C facilitates the sharp increase of DRX fraction. The occurrence of DRX reduces dislocation density, which greatly softens the alloy. Besides, more α2 grains generate at γ grain boundary and grain boundary/twin intersection during creep, and maintain Blackburn orientation relationship with γ grains. This is the result of stress-induced γ→α2 phase transformation.

Measurement of Creep Stress Exponent of TC17 Titanium Alloy by Nanoindentation Method at Room Temperature.

The creep stress exponent is commonly employed to characterize the deformation mechanism during the steady-state creep stage, serving as an indicator of creep behavior. The creep phenomenon of high melting point metallic materials is not obvious at room temperature. However, the nanoindentation method proves suitable for investigating the creep properties of metallic materials under such conditions. Consequently, this paper places emphasis on measuring the creep stress exponent of TC17 titanium alloy at room temperature using the load preservation stage of the nanoindentation method with a constant loading rate. In order to investigate the effects of loading rate and maximum load on the experimental results, different loading rates were applied to the diamond Berkovich indenter to reach different maximum loads. The indenter was held under the maximum load for a duration of 360 s, and the relationship between the indentation strain rate and indentation stress during the holding process was used to obtain the creep stress exponent of the material at room temperature. The findings indicate that within the loading rate range of 1.25 to 15 mN/s and maximum load range of 50 to 300 mN, the influence on the experimental results is insignificant. Ultimately, the distribution range of the creep stress exponent for TC17 titanium alloy at room temperature was measured to be 8.524-8.687.

Dynamic Temperature Prediction on High-Speed Angular Contact Ball Bearings of Machine Tool Spindles Based on CNN and Informer

This study addressed the issues related to the difficulty of determining the operating status of machine tool spindle bearings due to the high rotational speeds and rapid temperature fluctuations. This paper presents an optimized model that combines Convolutional Neural Networks (CNNs) and Informer to dynamically predict the temperature rise process of bearings. Taking the H7006C angular contact ball bearing as the research object, a combination of experimental data and simulations was used to obtain the training dataset. Next, a model for predicting the temperature rise of the bearing was constructed using CNN + Informer and the structural parameters were optimized. Finally, the model’s generalization ability was then verified by predicting the bearing temperature rise process under various working conditions. The results show that the error of the simulation data source model was less than 1 °C at steady state; the temperature error of the bearing temperature rise prediction model was less than 0.5 °C at both the temperature rise and steady-state stages under variable rotational speeds and variable load conditions compared to Informer and Long Short Term Memory (LSTM) models; the maximum prediction error of the operating conditions outside the dataset was less than 0.5 °C, and the temperature rise prediction model has a high accuracy, robustness, and generalization capability.

Real-time coordination of multiple shuttle-conveyor-belts for inventory control of multi-quality stockpiles

A hybrid model predictive control formulation with continuous and discrete variables that models multiple crushed-ore stockpiles per conveyor-belt is proposed for better conveying and stockpiling performance. The aim is to minimize the inventory level or holdup squared deviations from targets by varying the fill-time, idle-time, or run-length of the shuttle-conveyor-belts’ tripper-cars over multiple stockpiles’ positions (the discrete actuation or manipulated variable). In the problem, amounts of crushed-ore dropped by gravity from conveyor-belts fill up the upper-level of the stockpiles considering quality balances to specify blended ore by the mixtures of the material dropped by synchronized shuttle-conveyor-belts’ tripper-cars. The problem is solved as a mixed-integer quadratic programming (MIQP) that uses amount-of-quality balances as a linear (LP) approximation, tightening the MIQP-solutions to schedules of simultaneous blending of different quality shuttle-conveyor-belts’ raw materials. Results of the initialization and steady-state stages of the inventory-control and logistics-quality optimization highlight the modeling and solution strategies.

Static and Pseudo Static Analysis of Embankment Slope Stability of Bener Dam, Purworejo Regency, Central Java

The Bener Dam is considered as one of the largest rock-fill dams in Indonesia. This dam will impact the inundation area of three main villages in the Wonosobo and Purworejo regency. Since this zoned embankment dam consists of rock-fill and the core material, the stability of the dam slope has to be done to ensure that the dam is stable against any failures including the seismic effects. Moreover, the seismic coefficient in the study area in the seismic analysis of the large dam slope is needed to be used in the analysis which is not yet done from the previous studies. This paper presents the analysis of the embankment slope stability of the Bener dam under static condition and pseudo static condition. The analysis takes into account the end stage of construction, the steady-state stage, and rapid drawdown stage. The results of utilizing the Finite Element Method to analyse the slope stability demonstrates that the dam embankment slopes are stable under static and seismic stress conditions in all the reservoir condition stages. After applying the seismic loading, the result of safety factor of slope stability is reduced while the rapid drawdown stage has the lowest safety factor.

On the origin of stress-strain relationships, the evaluation of softening coefficients, and mechanistic models for work hardening

The constitutive stress-strain relationships for structural alloys under tensile loading are reconstructed by assessing the form and mechanism of work hardening relationships. The stress-strain relationships are derived that reproduce both the Hollomon and Voce expressions. The Voce expression well-reproduces the later steady-state stage of work hardening whereas the Hollomon relationship provides a better fit just beyond the proportional limit. Using the Voce relationship, sequential linear regions can be considered for the variation of work hardening with stress, wherein the slope is defined as the softening factor. It's found that the work hardening and softening factor increase as deformation initially progresses beyond yield but decrease once the steady state condition is achieved as the total plastic strain continues up to the instability. By evaluating the initial linear stage beyond yield, a formulation is developed to compute the dislocation activation volume for the onset of plastic deformation. In addition, a new constitutive nonlinear work hardening behavior is used to derive a new stress-strain relationship for the deformation of alloys that work harden to the strength instability as derived from a statistical mechanics of assessment of work hardening behavior. Utility is demonstrated for the wide range of stress-strain behavior that is observed for the additively manufactured Ti–6Al–4V alloy.

Enhanced frequency of transcription pre-initiation complexes assembly after exposure to UV irradiation results in increased repair activity and reduced probabilities for mutagenesis.

In addition to being essential for gene expression, transcription is crucial for the maintenance of genome integrity. Here, we undertook a systematic approach, to monitor the assembly kinetics of the pre-initiating RNA Polymerase (Pol) II at promoters at steady state and different stages during recovery from UV irradiation-stress, when pre-initiation and initiation steps have been suggested to be transiently shut down. Taking advantage of the reversible dissociation of pre-initiating Pol II after high salt treatment, we found that de novo recruitment of the available Pol II molecules at active promoters not only persists upon UV at all times tested but occurs significantly faster in the early phase of recovery (2 h) than in unexposed human fibroblasts at the majority of active genes. Our method unveiled groups of genes with significantly different pre-initiation complex (PIC) assembly dynamics after UV that present distinct rates of UV-related mutational signatures in melanoma tumours, providing functional relevance to the importance of keeping transcription initiation active during UV recovery. Our findings uncover novel mechanistic insights further detailing the multilayered transcriptional response to genotoxic stress and link PIC assembly dynamics after exposure to genotoxins with cancer mutational landscapes.

Creep failure characteristics and characterization of constitutive behaviors of jointed sandstone under multi-level loading of seepage pressure

To study creep failure behaviors of jointed rock mass with seepage pressure as the main damage driving force, creep tests under multi-level loading of seepage pressure were conducted on sandstone with different joint dip angles. In addition, a memory-dependent nonlinear seepage–creep model was established for jointed sandstone. The results show that jointed sandstone experiences three creep stages (initial, steady-state, and accelerated creep stages) in creep tests under multi-level loading paths of seepage pressure. Jointed sandstone with joint dip angles of 30° and 60° undergoes shear failure, while that with the joint dip angle of 45° is subject to tensile–shear failure. Under the same seepage pressure, the sandstone with the joint dip angle of 45° has a greater creep rate in the steady-state creep stage than that with joint dip angles of 30° and 60°. In the volumetric compression stage, the permeability increases at the instant of applying each level of seepage pressure, followed by gradual reduction and stabilization of permeability. In the volumetric dilation stage, the permeability gradually rises. The theory of memory-dependent derivative reflecting the time memory effect was introduced to establish the memory-dependent nonlinear viscoelastic–plastic seepage–creep model for jointed sandstone. The results obtained using the theoretical model conform to the test data. Moreover, the creep failure criterion of the rock was proposed. The creep acceleration starts to increase from 0 and the critical steady state transitions to a non-steady state, suggesting that the rock will soon be damaged. The calculation formula for critical time corresponding to the critical steady state of creep was also deduced. The critical time to onset of creep can serve as an early warning of the creep failure of rocks.

Investigation of three-step heat treatments on the microstructure and steady-state creep behaviors of (TiB + TiC + Y2O3)/α-Ti composite

The microstructure and steady-state creep behaviors of as-cast and heat-treated (TiB + TiC + Y2O3)/α-Ti composites were systematically investigated in this study. The relevant properties of the matrix alloy are also provided for comparative analysis. The matrix alloy exhibits the coarse Widmannstatten structure. After heat treatment, the microstructure of the composite transforms from the basket-weave structure to a trimodal structure with spheroidized TiC and Y2O3 particles and some merged TiB whiskers. Compared to the matrix alloy, the steady-state creep rates of the as-cast and heat-treated composites are decreased by 29% and 40%, respectively. After creep, serious β-Ti dissolution in the matrix alloy and the as-cast composite contributes to the instability of α/β interfaces and precipitated silicides. The morphology of β-Ti phases in the heat-treated composite remains stable during creep and many dislocations are observed inside the secondary α-Ti phases, which is the main reason for the improvement of the creep performance. Extensive dynamic recrystallization occurred during the steady-state creep stage, and the dislocation structure undergoes significant evolution, along with a large number of sub-grains and dislocation walls. The coarse reinforcements play a role in the particle stimulated nucleation, while the small TiC and Y2O3 spherical particles provide little contribution to dynamic recrystallization. Dislocation climbing is the main creep control mechanism, and the creep rate keeps the constant through dislocation rearrangement and dislocation annihilation.