Recrystallization Conditions Research Articles

Study of austenite grain growth and recrystallization behavior in pipeline steels containing niobium

Abstract The austenite grain growth and recrystallization behaviors of three pipeline steels with different Nb contents were investigated through reheating and thermal simulation compression experiments. The initiation conditions for dynamic and sub-dynamic recrystallization of austenite were analyzed, and sub-dynamic recrystallization equations in Avrami form were established. The influences of Nb content and deformation conditions on the evolution of grain size during austenite recrystallization was examined. The findings indicate that the austenite grain size of the three steels increases gradually with higher reheating temperatures, while the average grain size decreases with increasing Nb content. Sub-dynamic recrystallization initiation temperatures for the B150-steel, B145-steel, and 73-steel were found to be 920 °C for 10 s, 940 °C for 30 s, and 960 °C for 30 s, respectively. During high-temperature deformation, Nb in solid solution hindered recrystallization by impeding grain boundary and dislocation movement. At lower deformation temperatures, Nb(C, N) precipitation pinned grain boundaries and dislocations and consumed substantial free energy, thus competing with recrystallization. As Nb content increased, strain-induced precipitation became more pronounced, resulting in more effective inhibition of recrystallized grain growth.

Use of differential scanning calorimetry as a rapid, effective in-process check method for impurity quantitation of an early clinical batch of Giredestrant (GDC-9545)

Giredestrant (GDC-9545) is a selective estrogen receptor degrader (SERD) that was developed for treatment of ER+/HER2− metastatic breast cancer. An anhydrous crystalline tartrate salt was identified as the solid form suitable for clinical development. An early clinical batch of the active pharmaceutical ingredient (API)/drug substance failed to pass the GMP purity specifications owing to the presence of a substantial amount of high molecular weight impurities (oligomers), as determined by size exclusion chromatography. Several trial rework batches were manufactured using various re-slurry and recrystallization conditions to purge impurities in the drug substance to adhere to purity specifications. Based on the melting point depression of the API in presence of oligomers in these rework batches, a differential scanning calorimetry method was developed to quantify impurity content as a function of melting point onset of the API. This thermal analysis method was used as a surrogate for chromatography as a rapid, effective in-process check method for impurity quantitation to enable the timely release of the final reworked clinical batch. Post release, the % w/w oligomer value determined by calorimetry was in excellent agreement to that obtained by size exclusion chromatography.

Excellent combination of strength and ductility in austenitic lightweight steel achieved by warm rolling process

In this study, warm rolling was applied to Fe–28Mn–11Al–1C–5Ni (wt.%) austenitic lightweight steel, which realized the higher dislocation density and finer dislocation-cell structures, achieving a better mechanical properties with ∼2.0 GPa of yield strength and ∼6.8 % of total elongation than cold rolling in the same conditions. In the subsequent partial recrystallization condition, the numerous dislocations and substructures existed in warm rolled steel provide more heterogeneous nucleation sites for grain refinement, resulting in the ultrafine-sized austenite and B2 with the size of 0.36 μm and 0.24 μm, respectively. Combined with grain refinement strengthening, solid solution strengthening, precipitation strengthening, and dislocation strengthening in the unrecrystallized austenite, the present steel shows an ultimate tensile strength of 1734 MPa, a uniform elongation of 21.7 % and a specific tensile strength of 267 MPa g−1 cm3. Such an excellent combination of strength and ductility induced by simple warm rolling and annealing is much better than previously reported for lightweight steels.

Calcite recrystallization and its impact on speleothem geochemistry

Speleothems are among the most important archives for past climatic and environmental change. Calcite recrystallization can modify the authigenic structure and geochemical composition of the speleothems and affect the reliability of calcite stalagmites as repositories of authigenic geochemical proxies of past climates and environments. The criteria for distinguishing primary from secondary speleothem calcite, and the conditions (open or semi-closed) of speleothem calcite recrystallization remain poorly understood. Thus, in this study, we investigated the fabric, geochemical composition, and recrystallization dynamics of a partially recrystallized calcite stalagmite (DDH-Z-2) from Didonghe Cave in Shaanxi Province, China, through petrographic observations, fluorescence microscopy, and geochemical analyses (stable isotopes, trace elements, UTh isotopes). We found that: (1) in the DDH-Z-2 stalagmite, open elongated columnar calcite recrystallized into compact elongated columnar calcite. Particulate organic matter and fulvic and humic acids were removed during recrystallization, while aromatic compounds were preserved and became incorporated into the secondary calcite; (2) calcite recrystallization was affected by multiple factors, including external fluid chemistry, primary calcite microstructure, and organic matter; (3) calcite recrystallization occurred under open, fluid-buffered conditions for alteration of the stable isotopes (δ18O and δ13C) and trace elements (Mg, Sr, U). The effect of external fluid composition on trace element (Mg, Sr) composition of secondary calcite varied across the stages of calcite recrystallization. Caution should, therefore, be exercised when using geochemical proxies in stalagmites composed of inclusion-free elongated columnar calcite: such calcite is likely to be recrystallized, and thus record the composition of reactive fluids at the time of recrystallization. Regarding the geochemical system of speleothem diagenesis, the contribution of the parent material and the sources of reactive fluids are key factors to consider.

Investigation on hot deformation behavior and microstructure evolution of superaustenitic stainless steel S31254 during elevated temperature compression testing

The study thoroughly investigated the hot deformation behavior and microstructure evolution of superaustenitic stainless steel S31254. Hot compression tests were conducted at temperatures ranging from 950 °C to 1200 °C and strain rates of 0.01–10 s−1. The flow behavior of S31254 is influenced by adiabatic heating, particularly at high strain rates. The critical conditions of dynamic recrystallization for various deformation conditions were calculated based on the “double differential method.” An rise in deformation temperature or a reduction in strain rate reduces critical stress. Using the Arrhenius equation and Zener-Hollomon parameter to represent the deformation parameters, a linear connection between peak stress and dynamic recrystallization critical conditions was determined. Electron backscattering diffraction and transmission electron microscopy were used to characterize the microstructure under various deformation conditions. The dynamic softening of superaustenitic stainless steel is mainly achieved through dynamic recrystallization. The recrystallized grains are driven by distorted energy to nucleate preferentially at high-angle grain boundaries and grow towards high misorientations. Discontinuous dynamic recrystallization characterized by grain boundary bowing out is the main recrystallization mechanism in S31254. However, at high temperatures and low strain rates (1200 °C, 0.01 s−1), the dynamic recrystallization process shifts from discontinuous to continuous, with subgrain coalescence serving as the nucleating mode.

Matrix-assisted laser desorption/ionization matrix incorporation evaluation algorithm for improved peak coverage and signal-to-noise ratio in mass spectrometry imaging.

Despite decades of implementation, the selection of optimal sample preparation conditions for matrix-assisted laser desorption/ionization (MALDI) imaging is still ambiguous due to the lack of a universal and comprehensive evaluation methodology. Thus, numerous experiments with different matrix application conditions accompany a translation of the method to novel sample types and matrices. Mouse brain tissues were covered with 9-aminoacridine through sublimation, followed by recrystallization in vapors of 5% (v/v) methanol solution in water. The samples were analyzed by MALDI time-of-flight mass spectrometry, and the efficiency of lipid and small-molecule ionization was evaluated with different metrics. We first investigate the dependency of matrix density and recrystallization conditions on the thickness of an analyte-empty matrix layer to roughly evaluate the laser shot number required to obtain an intense signal with minimal noise. Then, we introduce metrics for the analysis of small imaging datasets (small sample regions) of model samples based on median quantity of peaks in spectra (medQP) and weighted median signal-to-noise ratio (wmSNR). The evaluation of small regions and taking median values for metrics help overcome the sample heterogeneity and allow for the simultaneous comparison of different acquisition parameters. Here, we propose a methodology based on gradual laser ablation of small regions of sample and further implementation of weighted signal-to-noise ratio to assess various matrix application conditions. The proposed approach helps reduce the number of test samples required to determine optimal sample preparation conditions and improve the overall quality of images.

Crystalline Porous Organic Frameworks Based on Multiple Dynamic Linkages

AbstractA novel class of crystalline porous materials has been developed utilizing multilevel dynamic linkages, including covalent B−O, dative B←N and hydrogen bonds. Typically, boronic acids undergo in situ condensation to afford B3O3‐based units, which further extend to molecular complexes or chains via B←N bonds. The obtained superstructures are subsequently interconnected via hydrogen bonds and π–π interactions, producing crystalline porous organic frameworks (CPOFs). The CPOFs display excellent solution processability, allowing dissolution and subsequent crystallization to their original structures, independent of recrystallization conditions, possibly due to the diverse bond energies of the involved interactions. Significantly, the CPOFs can be synthesized on a gram‐scale using cost‐effective monomers. In addition, the numerous acidic sites endow the CPOFs with high NH3 capacity, surpassing most porous organic materials and commercial materials.

Crystalline Porous Organic Frameworks Based on Multiple Dynamic Linkages.

A novel class of crystalline porous materials has been developed utilizing multilevel dynamic linkages, including covalent B-O, dative B←N and hydrogen bonds. Typically, boronic acids undergo in situ condensation to afford B3O3-based units, which further extend to molecular complexes or chains via B←N bonds. The obtained superstructures are subsequently interconnected via hydrogen bonds and π-π interactions, producing crystalline porous organic frameworks (CPOFs). The CPOFs display excellent solution processability, allowing dissolution and subsequent crystallization to their original structures, independent of recrystallization conditions, possibly due to the diverse bond energies of the involved interactions. Significantly, the CPOFs can be synthesized on a gram-scale using cost-effective monomers. In addition, the numerous acidic sites endow the CPOFs with high NH3 capacity, surpassing most porous organic materials and commercial materials.

Investigation into the Hot-Forming Limit for 22MnB5 Hot-Forming Steel under a Stamping Process

Hot-forming technology for 22MnB5 hot-forming steel (22MnB5 HF steel) plates has been widely used in the automobile manufacturing industry in recent years. Physical simulation and numerical modeling were carried out in order to determine the forming limit of a 22MnB5 steel plate for the stamping process. The deformation experiments were performed in a temperature range of 600~900 °C and a strain rate range of 0.1~10 s−1. In the uniaxial tensile tests, it was found that at the forming temperature of 600 °C, the condition of dynamic recrystallization was not fully reached, and thus the corresponding tensile strength was much larger than that at other deformation temperatures. In the numerical simulation of bulging experiments, it was found that 22MnB5 steel had good formability when the initial deformation temperature was high and the forming speed was low by using the instability criterion, combining the maximum punch force and strain path transition. The forming limit diagram of 22MnB5 steel at a temperature of 700 °C and tool speed of 25 mm/s was obtained by means of simulation and a hot stamping experiment. The establishment of the forming limit of the 22MnB5 steel plate can provide theoretical and technical guidance for the hot-forming process.

A preparation of debranched waxy maize starch derivatives: Effect of drying temperatures on crystallization and digestibility

The impact of recrystallization conditions and drying temperatures on the crystallization and digestibility of native waxy maize (Zea mays L.) starch (NWMS) was explored. This study involved subjecting NWMS to concurrent debranching and crystallization at 50 °C for up to 7 days. Samples were collected by oven-drying at 40, 60, and 80 °C for 24 h. This simultaneous debranching and crystallization process increased the resistant starch (RS) content by approximately 48 % compared to the native starch. The drying temperatures significantly influenced the RS content, with samples dried at 60 °C exhibiting the lowest digestibility. X-ray diffraction (XRD) analysis revealed that most crystals demonstrated a characteristic A-type arrangement. Debranching and crystallization processes enhanced the crystallinity of the samples. The specific crystal arrangement (A- or B-type) depended on the crystallization conditions. A 15 min heating of NWMS in a boiling water bath increased the digestible fraction to over 90 %, while the samples subjected to debranching and crystallization showed an increase to only about 45 %. A linear correlation between starch fractions and enthalpy was also observed.

Research on the Hot Deformation Process of A100 Steel Based on High-Temperature Rheological Behavior and Microstructure.

To obtain the optimal hot deformation process, the rheological and dynamic recrystallization behaviors of A100 steel were researched through isothermal compression tests. Firstly, a Hensel-Spittel constitutive model was established based on the stress-strain curves. Secondly, dynamic recrystallization percentage and grain size models were established to identify the necessary conditions for complete dynamic recrystallization. Finally, microstructural analysis was employed to validate the accuracy of the recrystallization model. The results indicate that the flow stress is highly sensitive to both the strain rate and the temperature, and the HS model demonstrates a high predictive accuracy, with a correlation coefficient of 0.9914. There exists a contradictory relationship between decreasing the average grain size and increasing the recrystallization percentage. The higher the percentage of dynamic recrystallization, the larger the average grain size tends to be. This situation should be avoided when devising the actual processing procedures. The optimal hot working processes for achieving complete dynamic recrystallization and a smaller average grain size are as follows: a strain equal to or greater than 0.6, a temperature between 1193 and 1353 K, and a strain rate between 0.1 and 1 s-1.

Artificial Neural Network-Based Critical Conditions for the Dynamic Recrystallization of Medium Carbon Steel and Application

This study presents a novel and thorough approach to comprehending and simulating the DRX process while hot compressing steel. To achieve this goal, we studied the high-temperature deformation behavior of a medium-carbon steel through hot compression testing on a Gleeble-3800 thermomechanical simulator over a broad range of strains, strain rates, and temperatures. We also employed an artificial neural network (ANN) to model the thermo-visco-plastic behavior with a flow law. The precision of quantifying the DRX volume fraction is dependent on critical conditions, which are essential for both analytical model evaluation and numerical implementation in finite element software. This study proposes a second ANN, serving as a universal approximator, to fit the data required for DRX critical condition calculations, whereas the Johnson–Mehl–Avrami–Kohnogorov (JMAK) model served as an analytical tool to estimate the DRX volume fraction, which underwent validation through experimental measurements. A numerical implementation of the JMAK model was conducted in ABAQUS software and compared against experimental data by means of microstructure analysis. The comparison revealed a strong correlation between the simulation and experiment. The study investigated the impact of temperature, strain, and strain rate on DRX evolution. The findings showed that DRX increases with rising temperature and strain but decreases with increasing strain rate.

Comparison of Solidification Microstructure Evolution of Al-10Si and Recycled Aluminium Beverage Can Strips Made in a Strip Caster

A strip caster was used to cast two types of aluminium alloys: an almost eutectic Al-Si alloy (Al 10 Si) with contaminants of 0.6 Fe, 0.2 Pb, and 1.4 Sn, which exhibits a polyphase microstructure upon solidification, and recycled aluminium beverage cans made from Al 0.8 Mn alloy containing 0.4 Si, 0.5 Fe, and 0.1 Mg, which has a monophase microstructure upon solidification. The molten materials were poured at 650 oC (Al 10 Si) and 670 oC (Al 0.8 Mn, 0.4 Si, 0.5 Fe, 0.1 Mg) on a cooling slope specially designed to obtain a semisolid material. This semisolid material was then dragged between rolls at a rate of 0.2 m/s to obtain high-quality metal strips. There was less eutectic modification with larger Al-α grains in the middle region of the sheet between the fine eutectic layers, indicating a lower cooling rate. However, during the recycling of aluminium beverage cans, large grains were formed with a columnar structure at the interface of the rolls, and semisolid melts with cracks were formed between the columnar grain boundaries owing to the compression of the rolls. The middle of these grains contained smaller equiaxial grains that were subjected to dragging. The as-cast specimens were submitted to homogenisation heat treatment at 560 oC for a period of 10 h and cooled to room temperature before being cold rolled (Temper H18) and recrystallised (Temper O) to examine the effect of these treatments on the tensile mechanical properties. During cold rolling (Temper H-18), grain alignment occurred with a yield stress, maximum stress, and elongation of 209.5 MPa, 210.1 MPa, and 2.8%, respectively. The strength decreased (yield stress of 58 MPa and maximum stress of 120.2 MPa) under recrystallisation conditions (Temper O), but the ductility increased (8.9%). This is in contrast to the Al-Si (Al 10Si) strip, which exhibited a yield stress, maximum stress, and elongation of 103.3 MPa, 128.7 MPa, and 1.9%, respectively. The A1 10Si strips also fractured during cold rolling, indicating high material fragility.

Solid‐state Chromism of Zwitterionic Triarylmethylium Salts

AbstractZwitterionic triarylmethylium dyes 1 and 2 were synthesized by using a synthetic unit of a tetraarylborate. The zwitterionic structure of 1 and 2 exhibits varied molecular assembly and induces charge transfer transition. These properties gave them specific optical features such as solvatochromism and mechanochromism in the solid state, that is, the green solid of 2 changes to yellow or red solid by dissolution & evaporation or grinding, respectively. The three colors were reproduced independently in different crystal forms, which were prepared from different recrystallization conditions. The diffuse reflectance measurement and powder X‐ray diffraction demonstrated the correlation between the colors and the solid‐state structures. The single crystal X‐ray analysis revealed face‐to‐face dimeric assembly in each crystal. Among the crystal structures, the intermolecular distances and packing patterns were notable differences. Based on these results, it can be suggested that unique color change of zwitterionic triarylmethylium dyes originates from the alternation of intermolecular interactions.

Ti‐in‐zircon and Ti‐in‐quartz thermometry using electron probe microanalysis: A promising approach in retrieving thermal conditions of granulite facies metamorphism and felsic magmatism in the Sandmata Complex, Aravalli Craton (NW India)

The titanium (Ti) concentrations in zircon and quartz and corresponding thermometers have been regarded as powerful monitors that constrain petrogenetically meaningful temperature conditions of crystallization and metamorphism. The precise measurement of trace elements by electron probe microanalyzer (EPMA) is quite challenging as their x‐ray intensities are only slightly higher than the Bremsstrahlung background, leading to significant errors while quantifying the elemental abundances (e.g., Ti‐in‐zircon). We present EPMA‐based protocols for analysing Ti concentrations in zircon and quartz by considering recent analytical and instrumental improvements. High counting times at peak and background positions, simultaneous acquisition of Ti in multiple (three) spectrometers and data processing using the non‐central chi2 test for risk determination in sub‐counting method were employed in Ti‐in‐zircon and Ti‐in‐quartz protocols. Applying these protocols to the Mongolian garnet, San Carlos olivine and NIST 610 glass standards yielded Ti concentrations of 0.60 ± 0.02 wt%, 18 ± 3 ppm and 437 ± 26 ppm (in ±2σ), respectively. The Ti concentrations obtained from these standards are consistent with those published based on high‐precision analytical methods. We use the existing Ti‐in‐zircon and Ti‐in‐quartz thermometers to understand the thermal evolution of various lithologies in the Sandmata Complex, Aravalli Craton (north‐western India). The investigated samples include garnet–biotite gneiss, migmatite gneiss, mafic granulite and Anjana granite. The Ti‐in‐zircon temperatures calculated from the patchy‐zoned zircon cores yield HT–UHT conditions (892–959°C) for garnetiferous granite gneiss, migmatite gneiss and mafic granulite, whereas the zircon overgrowths yield temperatures of 725–871°C. The homogeneous zircon cores from Anjana granite yield temperatures (914–984°C) comparable to zirconium saturation conditions (920–960°C), indicating zircon crystallization from “hot” granitic melt. The oscillatory overgrowths on the zircon core obtain variable temperature conditions for inner overgrowth (811–877°C) and outer overgrowth (714–782°C), suggesting the episodic growth of zircon grains from different magma pulses. Additionally, the application of pressure‐dependent Ti‐in‐quartz thermometry yields quartz recrystallization conditions for garnet–biotite gneiss (430–556°C), migmatite gneiss (423–593°C), mafic granulite (430–679°C) and Anjana Granite (444–533°C). The combination of Ti‐in‐zircon thermometry, Ti‐in‐quartz and conventional thermobarometry demonstrates cooling histories for various high‐grade metamorphic and magmatic rocks in the Sandmata Complex. Based on this study, we emphasize that trace element thermometers can decipher high‐temperature metamorphism, which is otherwise erased in conventional thermometers due to diffusional readjustments during long‐lasting near‐peak and post‐peak metamorphism.

Microstructure evolution and constitutive modeling of as-cast A356 aluminum alloy in semi-solid deformation regime

The present work deals with the semi-solid deformation behavior of A356 aluminum alloys with an emphasis on microstructure evolution and constitutive modeling. The main idea of this research is based on investigating the semi-solid deformation behavior starting with primary dendritic cast structure, instead the conventional approach in which a feedstock is prepared through the various spheroidization process. Toward this end, hot compression tests in the semi-solid temperature range (580, 590, and 600 °C) under different strain rates (0.001, 0.01, 0.1 s−1) and different initial holding times (1, 7, and 14 min) have been conducted. Compared with the thixotropic deformation in which the solid globules slide within the liquid matrix through lubricated flow mechanisms, in the present case, the strain compensation through the deformation of solid grains was increased. The higher portion of the solid-grains from the applied strain provided a proper condition for substructure development and dynamic recrystallization in the semisolid temperature range. The penetration of the liquid phase along the newly developed boundaries was introduced as another factor influencing on the softening behavior of the material. Under these conditions, the specimens were deformed up to the high strain level (>0.5) without creating cracks or tearing under very low stresses less than 2 MPa. A phenomenological-physical constitutive equation was also developed considering deformation parameters (temperature, strain rate, and strain) and material's parameters (grain size, strain rate sensitivity, viscosity) which was capable of predicting the semisolid flow stress behavior of the material.

High strength and plasticity TiBw/TA15 composites with a novel columnar network structure

In this paper, a novel columnar network structure reinforced TiBw/TA15 composites with excellent strength and high plasticity have been designed and prepared. To study the strengthening mechanism, the effects of the columnar network structure on the microstructure evolution and mechanical properties of the composites were investigated. The columnar network structure could effectively strengthen the grain boundary of the high temperature β phase and then enhanced the strength of the composites. At the same time, during the hot extrusion process, TiBw hindered the movement of dislocations and brought high distortion energy, which provided a favorable condition for dynamic recrystallization (DRX) of the matrix. DRX decreased the dislocation density, refined the grains, and then improved the plasticity of the matrix. Therefore, the effective combination of strength and plasticity was achieved in the composites.

Grain Boundary Engineering and Its Effect on Intergranular Corrosion Resistance of a Ni-Cr-Mo Based C276 Superalloy

A Ni-Cr-Mo-based C276 superalloy was cold rolled to 5–40% and annealed at 1050 °C for 30 min. The microstructure and grain boundary character distribution after cold rolling and annealing were characterized. Grain refinement and a certain amount of coincident-site lattice (CSL) boundaries were obtained through recrystallization. The fraction of CSL boundaries reached peak at the cold rolling of 15% and annealing at 1050 °C for 30 min, which was the critical condition for completed recrystallization. In addition, sensitization treatments and double-loop electrochemical potentiokinetic reaction (DL-EPR) tests were applied to the cold rolled and annealed samples. The samples with a high fraction of CSL boundaries showed higher intergranular corrosion resistance as compared to the ones with a low fraction of CSL boundaries. It implies that the intergranular corrosion resistance of C276 superalloy can be enhanced by optimizing the grain boundary structure through cold rolling and annealing.

Separation and Purification of Taxanes from Crude Taxus cuspidata Extract by Antisolvent Recrystallization Method

Taxanes are natural compounds with strong antitumor activity. In this study, we first enriched taxanes by ultrasonic extraction and liquid–liquid extraction from Taxus cuspidata, then purified these taxanes by the antisolvent recrystallization method, and discussed the effects of four recrystallization conditions on the purity of eight target compounds. The most promising purification results were obtained using methanol as a solvent and water as an antisolvent. Response surface methodology (RSM) was used to further optimize the optimal purification conditions: when the crude extraction concentration was 555.28 mg/mL, an antisolvent to solvent volume ratio was 28.16 times, the deposition temperature was 22.91 °C, and the deposition time was 1.76 min, the purity of the taxanes reached its maximum. The scanning electron microscopy (SEM) results showed that recrystallization could effectively reduce the particle size of crude Taxus cuspidata and control the particle morphology. X-ray diffraction (XRD) and Raman spectrum experiments demonstrated that the amorphous state of the crude Taxus cuspidata did not change during the recrystallization process, and always remained amorphous. This recrystallization method can effectively improve the purity of taxanes in Taxus cuspidata, and is suitable for the preliminary purification of taxanes.

Hot deformation behaviors and dynamic recrystallization mechanism of Ti-35421 alloy in β single field

Hot deformation behaviors and microstructure evolution of Ti−3Al−5Mo−4Cr−2Zr−1Fe (Ti-35421) alloy in the β single field are investigated by isothermal compression tests on a Gleeble−3500 simulator at temperatures of 820−900 °C and strain rates of 0.001−1 s−1. The research results show that discontinuous yield phenomenon and rheological softening are affected by the strain rates and deformation temperatures. The critical conditions for dynamic recrystallization and kinetic model of Ti-35421 alloy are determined, and the Arrhenius constitutive model is constructed. The rheological behaviors of Ti-35421 alloys above β phase transformation temperature are predicted by the constitutive model accurately. The EBSD analysis proves that the deformation softening is controlled by dynamic recovery and dynamic recrystallization. In addition, continuous dynamic recrystallization is determined during hot deformation, and the calculation model for recrystallization grain sizes is established. Good linear dependency between the experimental and simulated values of recrystallized grain sizes indicates that the present model can be used for the prediction of recrystallized grain size with high accuracy.