Deformation Behavior Of Materials Research Articles

Pressure-dependent deformation in brittle diamond

Distinguished from ductile metals, in brittle covalent materials like diamond, hydrostatic pressure is a prerequisite for triggering the plastic deformation. Consequently, the theoretical framework rooted in equilibrium lattice proves inadequate in describing the behavior of brittle covalent materials, making it essential to include extrinsic hydrostatic pressure effects. Here, we take diamond as a model and introduce hydrostatic pressure in the calculation of generalized stacking fault energies (GSFE). A deformation mechanism transition from perfect dislocation slipping on {200} plane to the partial dislocation slipping on {111} plane when the hydrostatic pressure exceeds 100 GPa is revealed by the pressure-coupled GSFE and further authenticated by nanocompression and diamond anvil cell experiments. Such pressure-dependent deformation mechanism is attributed to the different pressure sensitivities of lattice volume expansion during different slip systems operating. Our works provide insights into the activation of slip systems in diamond at the atomic scale and a route to study the plastic deformation behavior of brittle covalent materials.

Characteristics of atomic removal and mechanism of damage formation in vibration-assisted nano cutting of copper-nickel alloy

Vibration-assisted machining technology can effectively improve the quality and efficiency of nano cutting, but the characteristics of atomic removal and the mechanism of damage formation have not been systematically studied. In this paper, copper-nickel alloy material is taken as an example. The characteristics of vibration-assisted nano cutting and the plastic deformation behavior of materials were revealed by molecular dynamics simulation. The simulation results show that vibration-assisted nano cutting reduces tangential force, lateral force, and total force, strengthens the anisotropy of atomic motion, and causes greater displacement and removal of Cu/Ni atoms. The intermittent contact is beneficial for the elastic recovery of workpiece atoms, releasing internal stress and atomic strain, reducing the depth of damage and the length of dislocation lines. The difference in surface/subsurface damage to the workpiece is relatively small with an amplitude of 1 Å. With amplitudes of 3 Å and 5 Å, and as the frequency increases, the complete lattice structure is destroyed, resulting in a significant decrease in the number of FCC structural atoms and RDF peak. However, an appropriate increase in frequency can increase the removal of Cu/Ni atoms, improve the topological structure, and reduce RMS. The HCP and BCC structural atoms affect the generation of dislocation lines, with an amplitude of 3 Å and a frequency of 7.5 GHz, achieving the minimum damage depth and dislocation line length. Excessive amplitude of 10 Å results in irreversibly severe damage to the surface/sub-surface of the workpiece. This study will provide a new approach for optimizing vibration-assisted nano-cutting technology and achieving low-damage nano cutting of alloy materials.

A DIC-based Taylor impact test by measuring inertia force from acceleration distribution to obtain uniaxial stress–strain behavior of pure aluminum

The digital image correlation (DIC) technique is widely used to capture several kinematical quantities fields including displacement, velocity, strain, strain rate and acceleration in various kinds of the mechanical tests with the deformation of specimen. Considering the nature of nonuniform deformation in Taylor impact test, except the mentioned fields, the axial stress distribution is also required to evaluate the deformation behavior of materials. Recently, a measurement method for axial stress distribution is proposed based on an assumption of bilinear internal force distribution in specimen. However, the measured result only gives an approximate result. Besides, because the satisfaction of the assumption limits to several conditions, only the result obtained at a particular moment and position region is reliable. On the other hand, it is possible to calculate the axial stress distribution from the momentum balance law to avoid the mentioned assumption if the axial acceleration distribution is captured by the DIC technique. Unfortunately, the feasibility and accuracy for the method has not been discussed yet, even though some challenges on introducing DIC technique to Taylor impact test has already been done. Here, a method based on momentum balance law and axial acceleration distribution is newly proposed to obtain the axial stress distribution. The stress–strain curve in Taylor impact test is obtained by a simultaneously spatial combination between the stress and strain distributions. Then, the feasibility of the proposed method is discussed computationally and experimentally.

EFFECT OF CRYSTALLOGRAPHIC ORIENTATION ON MATERIAL REMOVAL BEHAVIOR DURING HIGH SPEED SCRATCHING OF MONOCRYSTALLINE SILICON

Monocrystalline silicon has anisotropic attributes due to asymmetric and non-uniform interatomic lattice structures, which affects its deformation and fracture properties. This paper aims to investigate the effect of crystallographic orientation on the material deformation and removal behavior during high speed scratching of monocrystalline silicon. A high-speed scratching setup is developed which can achieve the highest scratching speed of 40 m/s. Inclined scratching experiments are conducted on (001), (110) and (111) crystallographic planes over the speed range of 1 m/s to 30 m/s. As the scratching depth increases, the ductile-to-brittle transition of silicon at different crystallographic orientations are analyzed. The experimental results suggest that scratching in the direction of "[" ¯("1" ) "10]" on (111) plane presents the largest critical residual depth of ductile-to-brittle transition. Phase transformation from Si-I to the phases of Si-IV and a-Si dominates ductile deformation of silicon during scratching process, while scratching tests in "[" ¯("1" ) "10]" direction on (111) plane demonstrates the largest degree of material amorphization. This study can provide guidance for optimizing processing parameters of monocrystalline silicon components with different crystallographic orientations.

Development of modular cryogenic indentation apparatus for investigating micro-region mechanical properties of materials

High-precision cryogenic micromechanical testing apparatuses are of significant importance in investigating the micro-region mechanical properties and deformation behaviors of materials at cryogenic temperatures. In this study, a modular cryogenic indentation apparatus was designed and developed utilizing a contact-atmosphere hybrid refrigeration technique with a minimum temperature of −150 °C. The temperature of both the indenter tip and the specimen was independently controlled through a dual-channel proportional–integral–derivative (PID) feedback loop to eliminate contact thermal drift to within 0.1 nm/s. The application of cryogenic nitrogen (N2) atmosphere refrigeration eliminated additional stiffness at the indenter tip completely. The feasibility of the apparatus was demonstrated through calibrations and tests conducted on standard fused silica and single crystal nickel. Highly accurate indentation curves and micro-region mechanical properties of single crystal nickel were obtained at variable cryogenic temperatures. With decreasing temperature, both slip bands and pile-up around residual indentation imprints were weakened. Notably, at −150 °C, the slip bands disappeared, and the phenomenon of pile-up was replaced by sink-in. This developed cryogenic indentation apparatus will be a powerful tool to reveal the effect of cryogenic temperatures on the evolution mechanisms of materials’ micro-region mechanical properties.

Dynamic tensile deformation behavior of AISI 316L stainless steel fabricated by laser-beam directed energy deposition

The dynamic deformation behavior of metallic materials is the key to crash-safe design in many applications, e.g., in the automotive sector. However, in the field of additive manufacturing, dynamic deformation properties have only been scarcely studied. Based on the intrinsic interrelationships of process parameters, post-process heat treatments and the resulting microstructure, the present study seeks to provide a holistic overview of the dynamic tensile deformation properties of AISI 316L stainless steel, fabricated by laser-beam directed energy deposition. Utilizing in situ digital image correlation, the local deformation behavior at varying strain rates from 100 s−1 to 1000 s−1 was unveiled. In combination with pre- and post-mortem microstructure analysis using electron backscatter diffraction and scanning transmission electron microscopy, the microstructural effects on the active deformation mechanisms were studied. The results show that twinning contributes to the overall deformation in the heat-treated condition owing to the weaker crystallographic texture. On the contrary, twinning is less prominent in the non-heat-treated condition due to its pronounced <001> texture. As a result of the differences in terms of active deformation mechanisms, superior fracture elongations are observed in heat-treated condition, which are rationalized by delayed necking due to a more homogeneous strain distribution along the gauge section. Independently from the sample condition, fractography analysis revealed a ductile mode of failure being characterized by equiaxed dimples on the fracture surfaces. Consequently, it can be concluded that AISI 316L stainless steel is excellently suited for dynamic tensile loading, although heat-treatment-depended differences have to be taken into account.

Identification of active slip modes in twinned bicrystals of GNS/Cu composite through intragranular misorientation axes analysis

Bicrystals serve as a simplified model system for studying the deformation behavior of polycrystalline materials. In this study, we fabricated graphene nanosheets (GNSs) reinforced copper (Cu) matrix laminated composites using electrophoretic deposition and subsequent vacuum hot-press sintering. Interestingly, the composite exhibited a bicrystal microstructure, with two types of adjacent crystals, i.e., denoted as crystal A (φ1 = 222.06, Φ = 40.54, φ2 = 82.5) and crystal B (φ1 = 141.36, Φ = 43.76, φ2 = 1.94), displaying a twin orientation relationship. To investigate the deformation behavior of the GNS/Cu composite, we conducted interrupted room temperature uniaxial tensile tests combined with Scanning Electron Microscope (SEM) Electron Backscatter Diffraction (EBSD) characterization. To identify the activated slip systems in the composites, we performed trace analysis, applied the Schmid Factor law, analyzed the deformation gradient tensor, and conducted intragranular misorientation axis (IGMA) analysis. The trace analysis revealed that slip systems with high Schmid Factor values were favored during tension. Moreover, the deformation gradient tensor elements of the primary slip systems in the two crystals confirmed the deformation features observed by SEM. However, crystal B exhibited a significant deviation in trace angle. Further IGMA investigation revealed that during tension, some slip systems, which were not favored by the Schmid Factor law, were also activated in crystal B. The activation of these slip systems in crystal B can be attributed to the large deviation in the trace angle. The findings in this work provide valuable insights for exploring the underlying deformation mechanisms in polycrystalline materials.

Effects of Ultra-Low Temperatures on the Mechanical Properties and Microstructure Evolution of a Ni-Co-Based Superalloy Thin Sheet during Micro-Tensile Deformation.

With the development of product miniaturization in aerospace, the nuclear industry, and other fields, Ni-Co-based superalloys with excellent overall properties have become key materials for micro components in these fields. In the microforming field, size effects significantly impact the mechanical properties and plastic deformation behavior of materials. In this paper, micro-tensile experiments at room temperature and an ultra-low temperature were carried out to study the effects of initial microstructure and deformation temperature on the deformation behavior of Ni-Co-based superalloy thin sheets. The results show that as the ratio of specimen thickness to grain size (t/d) decreased from 8.6 to 2.4, the tensile strength σb decreased from 1221 MPa to 1090 MPa, the yield strength σs decreased from 793 MPa to 622 MPa, and the elongation decreased from 0.26 to 0.21 at room temperature. When t/d decreased from 8.6 to 2.4, σb decreased from 1458 MPa to 1132 MPa, σs decreased from 917 MPa to 730 MPa, and the elongation decreased from 0.31 to 0.28 at ultra-low temperatures. When t/d decreased from 8.6 to 2.4, the surface roughness of the specimen increased from 0.769 to 0.890 at room temperature and increased from 0.648 to 0.809 at ultra-low temperatures. During the microplastic deformation process of Ni-Co-based superalloy thin sheets, the coupled effects of surface roughening caused by free surface grains and hindered dislocation movement induced by grain boundary resulted in strain localization, which caused fracture failure of Ni-Co-based superalloy thin sheets.

An optimized unibond dual-parameter peridynamic model for deformation and fracture simulation of quasi-brittle materials

Peridynamic is a nonlocal theory, which is an effective tool for predicting fracture in solids. The unibond dual-parameter peridynamic (UDPD) model can break through the Poisson's ratio limitation compared with the bond-based peridynamic model. However, the traditional algorithm for the integrated volume is designed according to the analytical value of partial length in the one-dimensional model, which will produce non-negligible errors for the two- and three-dimensional models. Besides, the classical UDPD model is restricted to ideal brittle materials rather than quasi-brittles, and the long-range force effect is generally omitted for simplified analysis. In this work, an optimized UDPD model is developed to overcome the above drawbacks in simulating the deformation and fracture of quasi-brittle materials. First, the novel algorithm to obtain a more accurate integrated volume is introduced into the UDPD model. Second, considering the long-range force effect and the deformation characteristics, the nonlinear constitutive force function coupled with the cosine type influence function is developed for the UDPD model. Then, the corresponding bond stiffnesses are derived. The proposed model is verified through several representative numerical applications, which suggests that the predicted results match well with the experimental observations and former simulations. It is indicated that the proposed model reveals a significant improvement in the convergence and precision of results, which can not only retain the stability of the classical UDPD model, but also precisely analyze the deformation behavior and damage evolution process of quasi-brittle materials.

An isotropic zero Poisson's ratio metamaterial based on the aperiodic ‘hat’ monotile

Metamaterials are synthetic materials, engineered to have desirable mechanical properties. This paper is concerned with a class of cellular metamaterials that minimise the Poisson's ratio, a metric that characterises the deformation behaviour of materials according to their orthogonal response to applied force. This secondary deformation is usually visually apparent as a sideways “bulge”, and can limit the longevity of multi-material components, from aircraft parts to medical implants, because of the interference shear stresses that arise between different materials due to deformations in different directions by different amounts. As a result, low Poisson's ratio can be a desirable mechanical property and the challenge of producing cellular metamaterials that have reduced Poisson's ratio has received significant research attention. However, solutions that have been proposed tend to be limited in their applicability, either because they are anisotropic, so behaviour varies greatly according to direction of the applied force, or because they are very low in relative density, so have low stiffness. Here we introduce a new cellular metamaterial, a honeycomb based on the recently discovered aperiodic ‘hat’ monotile, which offers nominally zero Poisson's ratio. Results from compression testing and computational modelling show that the behaviour of this metamaterial is isotropic, and is consistent across a range of relative densities, leading to the exciting conclusion that zero Poisson's ratio is possible for different stiffnesses. We envisage that this metamaterial will facilitate otherwise unfeasible technologies, such as morphing wing structures and medical devices that better mimic the behaviour of tissues such as cartilage.

Numerical Analysis of Recycled AA6061 Reinforced Alumina Oxide Undergoing Finite Strain Deformation Uniaxial Tensile and Taylor Cylinder Impact Tests

Recycling aluminum is a topic of high interest due to the global demand for aluminum-based products. This approach presents a great opportunity to address the environmental issues caused by the primary production of aluminum made from bauxite ore. In recent years, many researchers have explored the recycling of aluminum alloys, including reinforcement, to achieve better results and improve properties. However, there have been limited efforts to predict the deformation behaviour of such materials numerically. It is generally agreed that advancements in numerical analysis are important to accelerate progress and establish the application of newly developed materials. Therefore, this study aimed to numerically predict the deformation behaviour of recycled aluminum alloy AA6061 reinforced with Alumina Oxide, subjected to finite strain deformation of uniaxial tensile tests at different strain rates (6x10-1s-1 to 6x10-3s-1) and Taylor Cylinder Impact at different impact velocities (190ms-1 to 370ms-1) using the LS-DYNA simulation code. In this numerical analysis, a Simplified Johnson-Cook model is adopted and characterized. The simulation results, which were validated against published experimental data, showed good agreement, establishing appropriate numerical prediction capabilities for recycled aluminum alloys AA6061 reinforced with Alumina Oxide.

ANN-based structure peciliaties evaluation of polymer composite reinforced with unidirectional carbon fiber

At the moment, there is a growing interest in composite materials with matrices based on thermoplastic polymers; these materials are superior to traditional carbon fiber plastics due to higher fracture toughness and impact strength, low smoke generation during combustion, and high thermal and chemical resistance. The deformation behavior of such composite materials due to the high plastic deformation of the matrix differs from the behavior of traditional composites, which must be considered when performing calculations. In our study, as a model object, the features of the microstructure of single carbon thread impregnated with polysulfone were studied in order to evaluate the distribution of misorientation angles of elementary fibers, the degree of their damage, the thickness of the polymer matrix interlayers between elementary fibers in threads impregnated with more viscous thermoplastic binders. Statistical analysis of a large array of micrographs was carried out using specially developed algorithms for computer processing of electron microscopic images of a composite material. Algorithms for processing arrays of images using machine vision algorithms are proposed. Based on the analysis of the data array, the distributions of carbon fibers impregnated with polysulfone were plotted over the misorientation angle of the filaments and over the interfilament distance in the longitudinal and cross sections of the fiber. Using the machine learning method, an algorithm for detecting violations of the filament structure was implemented. The data obtained can be used to refine the calculations of the strength and deformation characteristics of composite materials with thermoplastic matrices.

Extrusion-based 3D-concrete-printing with different flow direction

Various flow directions are employed in the actual printing process, resulting in different printed results. This study primarily investigates how flow direction impacts the distribution of material mass, deformation behavior, and interlayer bond strength in printed structures. The results indicate that flow direction plays a pivotal role in regulating printing pressure. Increasing the flow direction can lead to higher deformation ratios, improved interlayer bond strength, elevated average compression pressure, and increased printing pressure in printed structures. However, this comes at the cost of reducing the area ratio of deposited filament. Achieving a balance between high buildability and desirable interlayer bond properties solely by adjusting the flow direction during the extrusion-deposition process may prove challenging. This study provides a theoretical basis and technical guidance for the selection and adjustment of flow direction in 3D printing process.

A comparative study on the effect of infill density, shape structure, and materials on tensile properties of FDM printed components

The Fused Deposition Modeling (FDM) 3D-printing method makes it possible to create high-complexity geometries quickly. The strength of the FDM printed components depends on various process factors, such as the infill density, the infill shape structure, the material, and a great number of other variables. This work evaluates the effect of infill structure and infill density on the tensile strength of different materials. PLA, ABS, and PETG materials were considered during the work with different infill densities and structures. It compares the deformation behavior of different materials with the same infill structures and density. The experimental results show that the tensile deformation of material depends on the infill structure and density. For PLA and ABS, triangular infill structures show higher tensile strength at each infill density, whereas for ASA tri-hexagonal structure shows higher strength. This work helps the researchers and academician to enhance their knowledge in the field of FDM process.

Optimization-based parameter search of support vector regression for high-temperature compression constitutive modeling of 25CrMo4 steel

An accurate intrinsic structural model is essential to describing the high-temperature deformation behavior of metal materials. Support Vector Regression (SVR) has strong regression analysis capabilities, but its application research in constructing constitutive models of 25CrMo4 steel still needs to be improved. In this study, we use grid search, particle swarm optimization, improved genetic algorithm, and improved gray wolf optimization to optimize SVR parameters. A constitutive relationship model for 25CrMo4 steel under high-temperature compression based on SVR was established through training using experimental data models. The predicted data of SVR constitutive models with different optimization algorithms were compared with experimental data. Statistical values, such as average absolute percentage error (AAPE), mean absolute percentage error (MAPE), and correlation coefficient (R2), were introduced to evaluate the accuracy of each model. The particle swarm optimization-SVR model achieved the best performance, with an AAPE of 0.455 38, MAPE of 0.489 09%, and R2 of 0.999 74. Furthermore, compared to other models, it requires the least time. This model has a higher accuracy than other commonly used instantaneous models. These findings can provide a basis for selecting appropriate deformation parameters and preventing hot working defects of 25CrMo4 steel, thus helping to improve the manufacturing process and material properties.

Modelling of the deformation behaviour of a magnetic hydrogel in a magnetic field gradient

An ink made of alginate and methylcellulose with embedded magnetite microparticles was developed for extrusion printing. Constructs, so-called scaffolds, are colonised with cells which can be activated by mechanical stimulation. In this work, a defined magnetic field gradient is applied to achieve non-contact deformation. However, the deformation behaviour or relevant material parameters of the hybrid material are unknown. While the properties were determined with experiments adapted to hydrogels, a separate experimental set-up for micro-computed tomography, adapting the Maxwell configuration, was developed to investigate the deformation behaviour. These analyses were performed depending on ageing and particle concentration. For these tests, strands were used as bending beams, since these are simple and well known systems. Firstly, a model for the bending curve was erected, which defines a range in which the real bending curve would be expected. It was compared with the measured bending curves. There was very good agreement for the first days. On day 14, the measured bending curves were still within the calculated range, but at the lower limit due to the shortcomings of the model as the violation of the small deformations condition at this point. Secondly, the bending as a function of incubation duration was observed by a series of radiograms when a magnetic field gradient was applied. From this, a functional approach was formulated to describe the system response. Some parameters have already been identified, for others a proposal is given. Thirdly, microscopic analyses were carried out to observe the effects of the field gradient on particle distribution and structure. It was revealed that a homogeneous particle distribution was found even after 2.5 h. Also, in the direction of the field gradient, no chains were formed and no damage of the network could be detected. The obtained results show, that the material is suitable for mechanical stimulation.

Confluent effects of initial dislocation microstructures on yield behavior in single-crystal tungsten at high temperature

Though it is well known that initial dislocation microstructures play an important role in the deformation behavior of materials, how dislocation microstructures affect the macroscopic properties is still subjected to intensive research due to their complexity. In this work, we use discrete dislocation dynamics (DDD) to understand the effect of initial dislocation microstructures on the dynamic yield behavior of single-crystal tungsten above the critical temperature (800 K). DDD results suggest that the dislocation source length and the dislocation density are responsible for the initial yield stress and the flow stress of tungsten under dynamic loading, respectively. As and increase, the plastic yield mechanism transforms from dislocation-source activation into dislocation-dislocation interactions, resulting in the initial yield stress decreasing and the flow stress increasing. The confluent effects of and on the steady-state flow stress can be unified by a linear relationship between and Our results could be a valuable piece that connects dynamic yield behavior to the initial dislocation microstructures.

Enhancing Output Signals of Sport Monitors Based on Triboelectric Porous PVDF Nanogenerators via Concaving Cells and Cell-Packing Structures.

Porous triboelectric polymer materials are widely used in portable sensors due to their lightweight and suitable mechanical performance, but their triboelectric properties need to be improved. Here, we propose a two-step strategy to concave the cell and cell-packing structure of triboelectric materials based on porous poly(vinylidene fluoride) (PVDF). The first step is to prepare triboelectric nanogenerators (TENGs) of PVDF with a concave cell-packing structure via oriented phase inversion. The second step is to concave the cells by radial and axial compression. The results reveal that the concavities in the cell structure at the radial direction and in the cell-packing structure at the axial direction improve the output signals of the porous PVDF TENG by ca. 150 and 110%, respectively. By contrast, the concaving in cell structure at the radial direction exerts a positive effect on triboelectric performance only when the radial compression strain is not bigger than 17.5%, especially when the cell wall is thin (ca. 0.85 μm). Meanwhile, the concavity-based strategy eliminates the irreversible deformation behavior of the porous PVDF material, enhancing its elasticity. The stability test shows that the sensor based on those materials is stable under 12,500 cycles, and the variance in the square derivation of output voltage is less than 1% during the cycle friction. Such stable and triboelectric-improved materials are assembled into sports-monitoring devices, providing an idea for the application of TENG in smart sensing.

Unraveling kinking: A plasticity enhancing failure mode in high strength nano metallic laminates

Kinking is an important and plasticity-enhancing deformation/failure mode in numerous mechanically anisotropic materials including high-strength nano metallic laminates (NMLs). However, our current limited understanding of the mechanics of kinking and its dependence on microstructural attributes is insufficient for thoroughly comprehending and eventually being able to control failure behaviors of materials. In this study, we investigate kinking dependencies on microstructural attributes in NMLs via in situ micropillar compression, multiscale microstructure characterization, dislocation dynamic simulations, and crystal plasticity modeling. By examining several NML systems (Cu/Fe, Ag/Fe, Al-4Mg/Fe), we demonstrate that the development of internal stresses during loading activates local layer-parallel glide triggering kinking in NMLs. Furthermore, this work reveals the effect of key microstructural features including layer thickness, layer waviness, interface barrier strength, and work hardening capacity on kink band formation in NMLs. More broadly, our efforts represent a generically applicable approach for probing large-strain deformation behavior of complex materials via synergetic modeling and experimental efforts.

Hot deformation behavior and flow stress modeling of coarse-grain nickel-base GH4151 superalloy ingot materials in cogging

Due to the high deformation resistance and poor thermal ductility of the new cast GH4151 alloy ingots, cracks are easy to occur during cogging process. For clarifying the effects of deformation parameters on microstructural evolution and dynamic recrystallization (DRX) nucleation mechanisms. In this work, the causes of crack formation and extension were first investigated using SEM and EBSD. The study revealed that the reasons for crack formation and propagation are the MC carbides at the original grain boundaries, large-size γ′ phase, residual eutectic phases, and tiny pores near the grain boundaries. Subsequently, a series of hot compression tests were performed using a Thermecamastor-Z thermo-mechanical simulator at temperatures ranging from 1080 °C to 1160 °C and a strain rate range of 0.01–10 s−1. The constitutive equation of the Arrhenius model and the hot working map was established, determining activation energy(Q) of 1086.58 kJ·mol−1. Large-size γ′ is coherent with the matrix. For the γ+γ′ dual-phase region, heterogeneous strain-induced dynamic recrystallization (HDRX) occurs, and discontinuous dynamic recrystallization (DDRX) is the main nucleation mechanism for DRX. However, for γ single-phase region, DDRX plays a more significant role. Furthermore, the MC phase (>1 μm) has different crystal orientations with the γ matrix and acts as sites for recrystallization through particle-stimulated nucleation (PSN). Finally, a fine and uniform grain structure can be obtained in the temperature range of 1120–1135 °C and the strain rate range of 0.1 s−1 to 1 s−1.