Degree Of Recrystallization Research Articles

Investigation of the Hot Deformation Behavior of 22Cr‐25Ni Austenitic Heat‐Resistant Steel by Combining Constitutive Model and Processing Map

The hot deformation behavior of 22Cr‐25Ni austenitic heat‐resistant steel at the temperatures of 950–1150 °C and strain rates of 0.01–10 s−1 is studied by isothermal compression test. It is found that the dynamic recrystallization (DRX) degree of the steel increases with the increase of temperature. The DRX degree decreases with the increase of the strain rate from 0.01 to 1 s−1, whereas the DRX degree increases with the increase of the strain rate from 1 to 10 s−1. The hot deformation activation energy is as high as 624.25 kJ mol−1 due to the addition of a large number of alloying elements. The typical strain compensation Arrhenius constitutive model established can be used to roughly predict the hot flow behavior of the steel. Furthermore, a modified model considering the influence of strain rate and deformation heat on the deformation process is proposed and showed higher accuracy (statistical parameters r = 0.994 and average absolute relative error = 4.59%). The DRX zone of the steel is determined to be 1080–1150 °C/0.01–0.1 s−1 through processing map analysis, representing the appropriate hot working zone. The microstructure corresponding to the instability zone in the processing map exhibits deformation concentration bands or necklace structures.

Microstructure and mechanical properties of Mg−Gd−Y−Zn−Zr alloy plates with different initial textures after hot rolling

The effects of initial textures on the microstructures and mechanical properties of rolled Mg−4.7Gd− 3.4Y−1.2Zn−0.5Zr (wt.%) plates were studied by optical microscope (OM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and tensile test. In the plate with an initial texture of 〈0001〉//RD (rolling direction), relatively coarse grains and bimodal basal texture are developed. However, in the plate with an initial texture of 〈0001〉//TD (transverse direction), finer grain size and strong 〈0001〉//ND basal textures are obtained due to the higher degree of dynamic recrystallization during rolling. Additionally, the irregular-shaped long-period stacking ordered (LPSO) phases are elongated along RD in both plates, which results in anisotropic load-bearing strengthening behavior, and further leads to a certain degree of yield anisotropy. The analysis of the strengthening mechanism shows that grain boundary strengthening is the most effective strengthening method in the plates. Because of the finer grain size and the strengthening caused by the elongated irregular-shaped LPSO phases, the rolled plate with an initial 〈0001〉//TD texture achieves the highest yield strength along RD.

Constitutive Model and Microstructure Evolution of Ti65 Titanium Alloy.

The hot deformation behavior and mechanism of Ti65 alloy with a bimodal microstructure were investigated by isothermal compression experiments conducted on the Thermecmastor-Z simulator equipment at temperatures ranging from 950 to 1110 °C and strain rates ranging from 0.01 to 10.0 s-1. The Arrhenius constitutive model, based on strain compensation, and Grey Wolf optimization-neural network with back propagation model (GWO-BP), were both established. The differences between the experimental and predicted value of flow stress were compared and analyzed using the two models. The results show that the prediction accuracy of GWO-BP in the two-phase region is higher than that of Arrhenius model. In the single-phase region, both methods demonstrated high prediction accuracy. Compared to the single-phase region, the flow stress of Ti65 alloy shows a higher degree of softening in the two-phase region. During deformation in the two-phase region, the initial lamellar α phase transformed from a kinked and elongated morphology to a globularized topography as the strain rate decreased. Boundary-splitting was the primary mechanism leading to the spheroidization process. The degree of recrystallization increased with the increase in strain rate during the deformation in the single-phase region, while dynamic recovery and strain-induced grain boundary migration were the main deformation mechanisms at a lower strain rate. Discontinuous dynamic recrystallization may be the dominant recrystallization mechanism under a high strain rate of 10 s-1.

Interface microstructural evolution, microhardness variation mechanism and 750 °C tensile behavior of the HIPed/FGed PM superalloy plastic bonded joints

In present research, a novel 3rd-generation powder metallurgy (PM) superalloys with different initial microstructures (hot isostatic pressed (HIPed) and fine grained (FGed)) were selected for plastic bonding (PB). Non-uniform deformation of the HIPed/FGed PB joint can be obtained due to the significant difference in flow behavior of the studied PM superalloys. Microstructure observation reveals that interface recrystallization dominates the successful healing of bonding interface. The lower dynamic recrystallization (DRX) degree accompanied with higher dislocation density can be detected in HIPed side, manifests that incomplete grain refinement would reduce the efficiency of interface healing and induce the generation of strain gradient at bonding interface. In addition, the microhardness variation of HIPed/FGed PB joint is fully dependent on the interface microstructural evolution. The average microhardness at the bonding interface about 501.0 HV is greatly associated with the neutralization effect of strain hardening from HIPed side and fine grain strengthening from FGed side. Special attention was focused on the fracture behavior and underlying mechanism of the HIPed/FGed PB joint in 750 °C tensile test. Owing to the grain size difference and huge strain gradient, the dislocations pile-up caused by localized stress concentration at bonding interface should be responsible for the brittle fracture of the HIPed/FGed PB joint. The whole process from damage initiation to final fracture includes the microvoids nucleation at grain boundaries, microvoids grow and coalesce into the microcracks, the extending microcracks aggregate to form main crack and then the brittle fracture occurs.

Rapid L-PBF printing of IN718 coupled with HIP-quench: A novel approach to manufacture and heat treatment of a nickel-based alloy

There has been a growing interest in additive manufacturing in recent years, with researchers actively working on improving component quality through adjustments to printing parameters, lead time, and productivity. Rapid L-PBF printing has emerged as an attractive approach to expedite component manufacturing. However, employing a rapid building strategy may lead to additional internal flaws, which can be addressed during a Hot Isostatic Pressing (HIP) cycle. In this study, Inconel 718 was L-PBF printed using two distinct strategies: one involving the creation of a dense 1 mm shell with loosely packed powders in the core and the other utilizing different sets of printing parameters for the shell and core, respectively. These strategies resulted in a 60% and 45% printing time reduction, respectively, compared with the time requirement for printing same-size cubic samples with optimized parameters. Additionally, full densification and porosity elimination were achieved through a HIP-quench approach, obviating the need for further heat treatment. The study presents the final microstructures and retained flaws, along with assessing the degree of recrystallization via EBSD analysis and evaluating mechanical properties using hardness measurements and compression tests.

Construction of a Predictive Model for Dynamic and Static Recrystallization Kinetics of Cast TC21 Titanium Alloy

In this study, hot compression experiments were conducted on cast TC21 titanium alloy using a Gleeble-1500D thermal simulation compression tester, and the hot-compressed specimens were heat-treated. The data obtained after analyzing the thermal compression of cast TC21 titanium alloy were analyzed to construct a thermal machining diagram with a strain of 0.8 and to optimize the machining window. This study investigated the microstructure of the alloy after hot pressing experiments and heat treatment, applying the study of the microstructure evolution law of cast TC21 titanium alloy. The analysis of the tissue evolution law established the dynamic and static recrystallization volume fraction as a function of heat deformation parameters. The results show that the optimal processing window for cast TC21 titanium alloy is a deformation temperature in the range of 1373 K–1423 K and a strain rate of 0.1 s−1. The increase in deformation volume and deformation temperature both favor recrystallization and make the recrystallization volume fraction increase, but the increase in strain rate will inhibit the increase in the recrystallization degree to some extent. The dynamic and static recrystallization equations for the cast TC21 titanium alloy at different temperatures were constructed. The experimental measurements of recrystallization volume fraction are in good agreement with the predicted values.

Effect of recrystallization degree on properties of passive film of super ferritic stainless steel S44660

Abstract The effect of the recrystallization degree on the properties of passive films formed in 0.1 M HNO3 solution for super ferritic stainless steel S44660 was examined in this study. The initial specimens, in their cold-rolled state, showed a high dislocation density, as observed through electron backscatter diffraction (EBSD) experiments. Analysis of potentiodynamic polarization (PDP) curves and electrochemical impedance spectroscopy (EIS) measurements suggested that with the increase of recrystallization degree, the corrosion current density reduced and the corrosion potential increased. As revealed by Mott–Schottky analysis, the passive film showed a dual structure of n-type and p-type semiconductors, with the carrier density of the passive film decreasing as the recrystallization degree increased. X-ray photoelectron spectroscopy (XPS) provided insights into the film composition, indicating that the Fe2O3 and Cr2O3 content, which improved the stability of the passive film, increased with the degree of recrystallization. In summary, the increase in recrystallization degree reduced the number of defects in the microstructure, thereby creating favorable conditions for the formation of highly protective passive films. The passive film formed after complete recrystallization exhibited enhanced corrosion resistance.

Effect of final rolling temperature on microstructure and intergranular corrosion resistance of an Al–Cu–Mg–Ag alloy

Connection of microstructure with corrosion properties of an Al-3.62Cu-0.9Mg-0.45Ag alloy in natural aging (NA) state and peak aging (PA) state at different final rolling temperatures (20 °C, 180 °C and 280 °C) are studied by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), X-ray diffraction (XRD), texture and electrochemical analysis. The results show that the deformation texture and recrystallization texture of T280-NA alloy account for the largest percentage with the largest degree of recrystallization. With the increase of final rolling temperature, the proportion of low angle grain boundaries (LAGBs) of NA alloy increases, the diameter, thickness and volume fraction of Ω phase in PA alloy decrease, and the grain boundary precipitates (GBPs) are gradually transformed from discontinuous distribution to continuous distribution. The grain boundary precipitates are also found to be consist of alternating S and θ phases and the width of precipitation free zones (PFZs) is essentially independent of final rolling temperature. The intergranular corrosion (IGC) resistance of T280-NA alloy and T20-PA alloy is the best, which is a result of the combined effect of GBPs, texture and grain boundary properties. In addition, this result is verified in this paper by studying the electrochemical properties of the alloy.

The dynamic recrystallization microstructure characteristics and the effects on static recrystallization and mechanical properties of Al–Mg–Si alloy

It is essential to clarify the dynamic recrystallization microstructure characteristics of age-hardened aluminum alloys and the effects on the static recrystallization microstructure and aging mechanical properties, with the aim of selecting the deformation conditions reasonably. This work investigated the evolution of the hot deformation and solid solution microstructures and aging mechanical properties of Al–Mg–Si alloy with deformation temperatures of 400–550 °C, strain rates of 0.01–10 s−1, and true strains of 0.2–0.8. Research has shown that it is advantageous for the DDRX and CDRX mechanisms to annihilate and rearrange dislocations simultaneously for forming deformation microstructure with uniform grain size at higher deformation temperatures and lower strain rates (such as 500 °C, 0.01 s−1). Additionally, the lower dislocation density in deformation microstructure facilitated the inhibition of static recrystallization during subsequent solid solution treatment, whereas lower deformation temperature and higher strain rate conditions should result in a greater degree of static recrystallization and reduce the uniformity of the solid solution microstructure. Hardness test results demonstrated that the deformation temperature of 480–520 °C and strain rate of 0.03–0.2 s−1 were the appropriate conditions for Al–Mg–Si alloy to attain finer and uniform grains and superior properties after solid solution treatment. The extruded samples within the above conditions (500 °C, 0.032 s−1) exhibited higher UTS and YS after solid solution and aging treatment, reaching 444 ± 2 MPa and 426 ± 4 MPa, respectively.

Recrystallization of Cellulose, Chitin and Starch in Their Individual and Native Forms.

Semi-crystalline natural polymers are involved in many technological processes. Biopolymers having identical chemical compositions can differ in reactivity in heterogeneous transformations depending on their crystal structure (polymorphic modification). This paper compares the crystal structure recrystallization processes occurring in natural polysaccharides (cellulose, chitin, and starch) in the individual form and as a component of native biomass. Aqueous treatment of pre-amorphized semi-crystalline biopolymers was shown to result in swelling, thus alleviating the kinetic restrictions imposed on the restoration of crystalline regions and phase transition to the thermodynamically more stable polymorphic modification. During recrystallization, cellulose I in the individual form and within plant-based biomass undergoes a transition to the more stable cellulose II. A similar situation was demonstrated for α- and β-chitin, which recrystallize only into the α-polymorphic modification in the case of both individual polymers and native materials. Recrystallization of A-, B-, and C-type starch, both in the individual form and within plant-based flour, during aqueous treatment, results in a phase transition, predominantly to the B-type starch. The recrystallization process depends on the temperature of aqueous treatment; longer treatment duration has almost no effect on the recrystallization degree of polymers, both in the individual form and within native materials.

Design of Heterogeneous Lamella Microstructure of 316L Austenitic Stainless Steel and Effect of Aging on Its Mechanical Behavior and Corrosion Properties

316L austenitic stainless steel (ASS) with a heterogeneous structure exhibits favorable mechanical properties at room temperature, promising excellent application potential. However, the thermal stability of 316L ASS with heterogeneous lamella structure (HLS) has not been adequately addressed yet. Herein, an HLS of 316L ASS is fabricated through 78% cold rolling followed by annealing at 750 °C for 13 min. The detailed investigation focuses on the influence of microstructure evolution on the mechanical properties and corrosion resistance of the alloy after aging at temperatures ranging from 350 to 550 °C for 100 h. The results show that a notable quantity of residual martensite persists even after annealing at high temperatures for a brief duration. The dislocation density of the test steel is reduced after long‐term aging treatment, and the residual martensite is further reversed into austenite during aging. In addition, the aging treatment also promotes further growth of nanocrystalline/ultrafine‐grained, which weakens the heterogeneous characteristics of HLS 316L ASS, resulting in a slight decrease in mechanical properties. However, the decrease in defect density and the enhancement of recrystallization degree are beneficial for eliminating most of the corrosion‐sensitive areas in the cold‐deformed structure, thereby improving the corrosion resistance.

Metamorphism (greenschist facia down) of terrigenous rocks in the northern part of the Kularsky gold-bearing district, Yakutia: mineral ratios with cleavage

In the Kularsky gold-bearing area, where 170 tons of gold were extracted from placers, primary gold deposits have not been well studied; therefore, their development requires detailed geological analysis including the study of rock metamorphism. A large Ulakhan-Sis anticline composed of Permian carbonaceous-terrigenous rocks is found on the northwestern flank of the Kular-Nersky folded belt of the Verkhoyano-Kolyma orogenic region. In this article we describe the material composition of carbonaceous-terrigenous rocks prevalent in the northern part of the Kularsky district. The degree of their postdiagenetic transformations varies from metagenesis in Triassic rocks to muscovite-chlorite and biotite subfacies of the greenschist facia of metamorphism in Permian rocks of the Ulakhan-Sis anticline. As the transition from metagenesis to muscovite-chlorite and biotite subfacies of metamorphism the degree of recrystallization of rocks, the grain sizes of the recrystallization of clastic quartz and the width of newly formed muscovite flakes are increasing, monazite, ilmenite, biotite flakes appear in rocks. These changes occur before the completion of formation in the rocks of the S1 slate cleavage.After the formation of the latter, mainly before the appearance of a later crenulation cleavage S2, crystallization of pyrite occurs in the rocks. Porphyroblasts of biotite and magnesiosiderite appear during the formation of a crenulation cleavage S2. The appearance of biotite during the formation of the S1 and S2 cleavages may correspond to the theories about the two-stage metamorphism of the rocks of the area. Thus, further metamorphism studies in this region are required.

Asymmetry in microstructure and mechanical properties of FSWed joints using a hemispherical tool tilted towards the retreating side

This study explores a novel technique using a hemispherical tool tilted towards the retreating side for friction stir welding AA6061-T6. Mechanical properties assessment proved the competitiveness of the new method over friction stir welding using a conventional tool with backwards tilting. The ultimate tensile strength, yield strength and elongation at break reach efficiencies of 60, 40 and 85% compared to BM. The new tool shape and the tilt towards the retreating side accentuate asymmetry in the stirred zone. Grain morphology and dislocations vary within the stirred zone when comparing the center and the sides due to different degrees of dynamic recovery and dynamic recrystallization. Dislocation density is increased at the center due to the complex stirring along an extended circular trajectory. The artificial aging at 180 °C for 18 h positively affects the joint strength while reducing the elongation at the break due to an inhomogeneous response of the softening zone to the aging. The highest hardness recovery within the stirred zone occurs at the center due to the higher concentration of strengthening precipitates which nucleate around dislocations. The weakest point of the weld identified in the stirred zone at the advancing side after artificial aging modifies the fracture behavior of the sample from a ductile to a rather ductile–brittle rupture.

Resistance of eogenetic dolomites to geochemical resetting during diagenetic alteration: A case study of the lower Qiulitage Formation of the Late Cambrian, Tarim Basin

Rare earth elements (REEs), carbon, oxygen and Mg isotopes have been widely used to explain the origin of dolomite, but dolomite may undergo complex diagenetic alteration during long geological processes, and whether the geochemical signals of precursor dolomite can be preserved is still unknown. In order to further explore the formation mechanism of dolomite and the influence of diagenetic alteration processes on geochemical parameters, this paper takes the thick-layer dolomite of the Lower Qiulitage Formation of the Late Cambrian in the Tazhong uplift area as an example and divides the dolomite into two categories through petrologic observation. One category is fabric-retentive dolomite (FRD), including algal clotted dolomite, algal psammitic or psammitic grain dolomite, and aphanocrystalline dolomite; the other category is fabric-destructive dolomite (FDD), including crystalline dolomite (CD) and siliceous dolomite (SD). Cation ordering, unit cell parameters, major/trace elements, REEs as well as C–O–Mg isotopes of the pure matrix powders of different types of dolomites are further analyzed. The results show that the dolomites are near-source/far-source seepage reflux type and sabkha type eogenetic origin, and the magnesium ions mainly come from Late Cambrian seawater; dolomite crystals of different sizes are the result of the precursor dolomite suffering varying degrees of recrystallization during the early diagenesis period, inheriting the original geochemical characteristics; hydrothermal alteration occurs in the late stage of diagenesis, with limited magnesium ions in the hydrothermal fluid. Its impact on the dolomite is mainly reflected in local dolomite distortion and a large amount of aphanocrystalline silica and coarse-grained quartz cement filling, which fails to obviously reset the geochemical information of the matrix dolomite. The above results demonstrate that, under favorable conditions, early genetic marine dolomites may resist geochemical resetting over time intervals of more than 400 million years.

Study on damage behavior of the outer horizontal target in the EAST lower divertor after plasma operations

The EAST lower divertor features a partially implemented flat-type structure, and visible damage has been observed, particularly at the outer horizontal target location after plasma operations. This study conducts a detailed analysis of the damage to the outer horizontal target. The findings reveal instances of plastic deformation, cracking, and even tungsten flake detachment at specific locations on the outer horizontal target. Furthermore, different degrees of recrystallization are identified in the tungsten plates after plasma operations, with a more pronounced effect closer to the surface of the tungsten plates. These observations offer pertinent insights for ongoing research into the microstructural enhancement design of tungsten materials and the enhancement of crack thresholds at the W/Cu interface.

Hot compression behavior and microstructure evolution of Mg-Gd-Y-Zn-Zr alloy

In this work, the hot compression behavior and microstructure evolution of Mg-8Gd-3Y-xZn-0.6Zr (x = 0, 1.5) alloys were investigated by Gleeble-1500D thermal simulation test machine, SEM, EBSD and other equipment. The results showed that, prior to hot deformation, the grain size of Mg-8Gd-3Y-1.5Zn-0.6Zr (1.5Zn) alloy was smaller than that of Mg-8Gd-3Y-0.6Zr (0Zn) alloy. Both alloys exhibited weak texture strength with predominantly large angle grain boundaries. The true stress-strain curve of the 1.5Zn alloy distinctly revealed dynamic recrystallization features. Notably, the 1.5Zn alloy exhibited higher peak stress and thermal activation energy compared to the 0Zn alloy. Furthermore, the 1.5Zn alloy demonstrated a lower critical strain for dynamic recrystallization, suggesting a heightened likelihood and increased degree of recrystallization. After hot deformation, the Mg-8Gd-3Y-xZn-0.6Zr alloy experienced a notable reduction in grain size, particularly evident in the 1.5Zn alloy, where the grains were smaller compared to the 0Zn alloy. Moreover, the texture strength of 1.5Zn alloy was obviously weaker than that of 0Zn alloy. Dynamic precipitation and dynamic recrystallization were more likely to occur at grain boundaries. Simultaneously, the constitutive model, hot processing map and recrystallization kinetics model were constructed for Mg-8Gd-3Y-xZn-0.6Zr alloy.

Методика прогнозирования зон скопления сероводорода в сильвинитовых пластах калийных рудников и экспресс-определения газоносности пород по сероводороду

Intensification of potash salt mining, widespread use of high-performance continuous miners, involvement of gasbearing formations in mining are accompanied by release of natural poisonous gases into the atmosphere of mine workings, which explains the need to ensure safe working conditions for the miners. The article presents the researche results that helped to develop a methodology for predicting accumulation zones of one of the most hazardous poisonous gases, i.e. hydrogen sulfide. A correlation was established between the hydrogen sulfide concentration, presence of organic substances and the content of magnesium chloride in the rocks. The article describes methods to determine the accumulation areas of hazardous sulfurcontaining gases based on the trench sampling and laboratory test data, which makes it possible to take timely protective measures to ensure safety of the miners. The developed method is based on creation of the correlation fields for various geochemical attributes such as the NaCl, KCl, MgCl2 content and others. A close correlation between the content of organic carbon in the rocks and magnesium chloride indicates the degree of salt recrystallization, as evidenced by an increase in the hydrogen sulfide content. In addition, the article describes an express method to determine the gas content in rocks, which enables a quick and accurate assessment of hydrogen sulfide concentration directly in the mine workings, thus providing the possibility of prompt response to the hazards. Thus, the methodology proposed by the authors serves not only to identify the potentially hazardous areas, but also to prevent dangerous situations associated with the release of poisonous gases in potash mines. The research and practical approaches described in the article as well as the developed recommendations contribute to enhancing the efficiency of mine ventilation, which in turn leads to minimization of the risks to health and life of the miners.

Effect of variable thickness cross rolling on microstructure gradient of 2205 duple stainless steel

Quantitative description of the complex relationship between rolling process and microstructure is crucial for improving the performance of 2205 duplex stainless steel products. In this work, four distinct rolling processes were used for three passes of hot rolling of 2205 duplex stainless steel. The study delved into the macroscopic morphology, microstructural gradients, and texture evolution of 2205 duplex stainless steel sheets in various rolling states. In addition, a data expansion method was used to expand the original experimental data, and the support vector machine model optimized by genetic algorithm was used to accurately describe the complex relationship between different rolling processes and microstructures. The results indicate that the proposed variable thickness cross-rolling method renders a more uniform microstructure in the rolled piece, with significantly refined grains and the formation of a distinct structural gradient. Among them, when using process 3 rolling, the grain size in the edge area of the plate after three passes of rolling is finer and the degree of recrystallization is higher, which is conducive to improving the problem of poor thermal plasticity at the edges and providing a basis for studying the suppression of edge crack damage in 2205 duplex stainless steel. In addition, the proposed machine learning model accurately predicted the grain size of plates in different rolling states, aligning closely with experimental findings.

α″ martensite engineering: A strategy to achieve high yield strength and low yield ratio synergy for dual-phase titanium alloy

To breakthrough the long-term contradictory issue of high yield strength and low yield ratio for titanium alloys, and achieving the superior balance between these two key mechanical parameters. We have proposed an efficient “Quenching → Cold deformation → Recrystallization annealing” (QCR) strategy, which realizes the high yield strength (900 MPa) and low yield ratio (0.74) synergy for a model Ti6Al4V5.5Cu (wt.%) alloy which characterized with the unique multi-scale heterogeneous structure. The developed QCR processing route is based on the subtle utilization of orthorhombic α″ martensite, which plays the various roles in each processing step. By elaborately manipulating the recrystallization degree, chemical stability, effective domain of β phase and αt nano-precipitates in β phase, the stress-induced α″ martensite transformation (SIM α″) can be controlled effectively and even postponed until after yielding induced by dislocation mechanisms, thus leading to substantially improvement of yield strength. After yielding, abundant proliferation of SIM α″which assisted by multi-scale α phases and their interactions are the fundamental reasons for achieving higher work-hardening ability, tensile strength (1215 MPa) and uniform elongation (11%). Thus, the core strategy to realize the excellent combination of high yield strength and low yield ratio is manipulating the activation sequence of the plastic deformation carriers.

Study on the Mechanism of CNTs Regulating the Microstructures and Properties of Al–Cu–Mg Alloy

The purpose of this study was to investigate the effect of carbon nanotube addition on the microstructure and mechanical properties of Al–Cu–Mg alloy composites. By analyzing the XRD results, it was deduced that the extruded and heat-treated composites, after the addition of CNTs, were preferentially grown on the (220) crystal plane. In addition, the distribution of carbon nanotubes at α-Al grain boundaries was observed by SEM and TEM. The incorporation of carbon nanotubes leads to an increase in the degree of recrystallization in the composite. It is worth noting that according to the study of the four strengthening mechanisms of dislocation strengthening, grain refinement strengthening, load transfer strengthening, and second stage strengthening, when the carbon nanotube content is 1.5 wt.%, the tensile strength (480.4 MPa) and yield strength (456.68 MPa) are significantly improved.