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The Soviet-Wan Chai border area provided valuable exploratory experience for the establishment and construction of new China, and contains a rich revolutionary spirit and the fine traditions of the Chinese nation. Therefore, it is important to disseminate and improve the effectiveness of the red culture of Suwanbeian District. From the perspective of animation IP communication, we propose suggestions in three aspects of IP image extraction and construction, development and operation, and communication and promotion to help the red culture of Suwanbeian District achieve better communication, in view of the problems in the current situation of red culture communication in Suwanbeian District.

Intrathecal (IT) idursulfase-IT for the treatment of cognitive impairment is being investigated in pediatric patients with neuronopathic mucopolysaccharidosis II (MPS II) in addition to intravenous idursulfase. In this article, we report the findings for 54 months of idursulfase-IT treatment in an ongoing phase I/II extension trial (NCT01506141).A total of 15 male participants with neuronopathic MPS II (aged 3-11 years at enrollment) who were previously treated with intravenous idursulfase entered the extension study. Idursulfase-IT 10 mg or 30 mg was administered monthly via an IT drug delivery device or lumbar puncture, if indicated. The primary endpoint was safety and tolerability; secondary endpoints included pharmacokinetics, cerebrospinal fluid glycosaminoglycan levels, and cognitive function.In total, 15 participants received a median (range) of 50 (18-55) idursulfase-IT doses. Idursulfase-IT was generally well tolerated; there were no life-threatening adverse events (AEs) or deaths. Most serious AEs were related to the IT drug delivery device; only 2 serious AEs were related solely to idursulfase-IT. After treatment with idursulfase-IT, cerebrospinal fluid glycosaminoglycans were decreased in all participants; these decreases were maintained. Cognitive function was stabilized in 3 of 4 testable participants at month 55.These long-term results support the clinical development of idursulfase-IT for patients with MPS II with cognitive impairment.

In this paper, high-strength ultrafine-grained (UFG) pure aluminum (Al) was successfully achieved via a two-step processing route including room-temperature ECAP process for continuously 16 passes and post liquid nitrogen cryo-rolling for 50% reduction. The two-step processing route was observed to produce ultrafine grains with an average grain size of 0.98 μm and has obvious advantages for the preparation of high-strength pure Al in terms of the strength-ductility synergistic effect, which endows the pure Al excellent UTS value of 180 MPa, good Ef of 17.7% and a very high increase ratio (about 84%) of strength. The high strength was mainly attributed to the outstanding fine-grain strengthening provided by the combination of large-pass ECAP and cryo-rolling. In addition, the better uniform elongation of ECAP-rolled pure Al than ECAPed one was primarily dictated by the enhanced strain hardening capacity and the elongated grain shape.

Two-thirds of patients with mucopolysaccharidosis II (MPS II; Hunter syndrome) have cognitive impairment. This phase 2/3, randomized, controlled, open-label, multicenter study (NCT02055118) investigated the effects of intrathecally administered idursulfase-IT on cognitive function in patients with MPS II. Children older than 3 years with MPS II and mild-to-moderate cognitive impairment (assessed by Differential Ability Scales-II [DAS-II], General Conceptual Ability [GCA] score) who had tolerated intravenous idursulfase for at least 4 months were randomly assigned (2:1) to monthly idursulfase-IT 10 mg (n = 34) via an intrathecal drug delivery device (IDDD; or by lumbar puncture) or no idursulfase-IT treatment (n = 15) for 52 weeks. All patients continued to receive weekly intravenous idursulfase 0.5 mg/kg as standard of care. Of 49 randomized patients, 47 completed the study (two patients receiving idursulfase-IT discontinued). The primary endpoint (change from baseline in DAS-II GCA score at week 52 in a linear mixed-effects model for repeated measures analysis) was not met: although there was a smaller decrease in DAS-II GCA scores with idursulfase-IT than with no idursulfase-IT at week 52, this was not significant (least-squares mean treatment difference [95% confidence interval], 3.0 [-7.3, 13.3]; p = 0.5669). Changes from baseline in Vineland Adaptive Behavioral Scales-II Adaptive Behavior Composite scores at week 52 (key secondary endpoint) were similar in the idursulfase-IT (n = 31) and no idursulfase-IT (n = 14) groups. There were trends towards a potential positive effect of idursulfase-IT across DAS-II composite, cluster, and subtest scores, notably in patients younger than 6 years at baseline. In a post hoc analysis, there was a significant (p = 0.0174), clinically meaningful difference in change from baseline in DAS-II GCA scores at week 52 with idursulfase-IT (n = 13) versus no idursulfase-IT (n = 6) among those younger than 6 years with missense iduronate-2-sulfatase gene variants. Overall, idursulfase-IT reduced cerebrospinal glycosaminoglycan levels from baseline by 72.0% at week 52. Idursulfase-IT was generally well tolerated. These data suggest potential benefits of idursulfase-IT in the treatment of cognitive impairment in some patients with neuronopathic MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

Enzyme replacement therapy with weekly infused intravenous (IV) idursulfase is effective in treating somatic symptoms of mucopolysaccharidosis II (MPS II; Hunter syndrome). A formulation of idursulfase for intrathecal administration (idursulfase-IT) is under investigation for the treatment of neuronopathic MPS II. Here, we report 36-month data from the open-label extension (NCT02412787) of a phase 2/3, randomized, controlled study (HGT-HIT-094; NCT02055118) that assessed the safety and efficacy of monthly idursulfase-IT 10 mg in addition to weekly IV idursulfase on cognitive function in children older than 3 years with MPS II and mild-to-moderate cognitive impairment. Participants were also enrolled in this extension from a linked non-randomized sub-study of children younger than 3 years at the start of idursulfase-IT therapy. The extension safety population comprised 56 patients who received idursulfase-IT 10 mg once a month (or age-adjusted dose for sub-study patients) plus IV idursulfase (0.5 mg/kg) once a week. Idursulfase-IT was generally well tolerated over the cumulative treatment period of up to 36 months. Overall, 25.0% of patients had at least one adverse event (AE) related to idursulfase-IT; most treatment-emergent AEs were mild in severity. Of serious AEs (reported by 76.8% patients), none were considered related to idursulfase-IT treatment. There were no deaths or discontinuations owing to AEs. Secondary efficacy analyses (in patients younger than 6 years at phase 2/3 study baseline; n = 40) indicated a trend for improved Differential Ability Scale-II (DAS-II) General Conceptual Ability (GCA) scores in the early idursulfase-IT versus delayed idursulfase-IT group (treatment difference over 36 months from phase 2/3 study baseline: least-squares mean, 6.8 [90% confidence interval: -2.1, 15.8; p = 0.2064]). Post hoc analyses of DAS-II GCA scores by genotype revealed a clinically meaningful treatment effect in patients younger than 6 years with missense variants of the iduronate-2-sulfatase gene (IDS) (least-squares mean [standard error] treatment difference over 36 months, 12.3 [7.24]). These long-term data further suggest the benefits of idursulfase-IT in the treatment of neurocognitive dysfunction in some patients with MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

The tension-compression asymmetric mechanical behavior of the AZ91 magnesium alloy with multi-heterogenous microstructure was investigated in comparison with its cast counterpart. The individual effect of different deformation modes in fine and coarse grains are clarified to reveal the underlying mechanism behind the asymmetric yield behavior by electron back-scatter diffraction analysis. The result demonstrated that the mechanical twinning prevailing in coarse grains is responsible for the yield asymmetry of the multi-heterogeneous alloy.

In the present work, we firstly and comparatively investigated the microstructure evolution and mechanical properties of AZ91 alloy processed by equal channel angular pressing (ECAP) combined with prior and post aging treatment. Both processes induce homogenous microstructures consisting of fine grains modified by uniformly dispersed spherical precipitates. The prior aging treatment facilitates a well-developed dynamic recrystallized microstructure with low dislocation density, and finer and more precipitates, while both processes induce comparable grain size. Thus, the prior aging treatment benefits to the occurrence of dynamic recrystallization during subsequent ECAP processing. Furthermore, both the strength and ductility of AZ91 alloy are enhanced and flexibly managed through ECAP with a combination of prior or post aging treatment. The post aging treatment is of benefit to the improvement in yield strength, while the prior aging treatment facilitates the more significant ductility enhancement.

Dynamic precipitation and recrystallization behaviors in Al-12.5 wt%Si-0.6 wt%Mg-0.1 wt%Ti alloy during hot-rolling and their impacts on mechanical properties were investigated by microstructure characterization and tension test. The results show that higher temperature suppresses the dynamic precipitation of Mg2Si phase to a great extent, however, larger reduction ratio enhances this behavior. Phase distribution maps by EBSD strongly indicate that rolling above 500 °C leads to significant dynamic recrystallization. Increasing either the rolling temperature or reduction ratio favors dynamic recrystallization and refines the recrystallized grains. The reduction ratio has more distinguished effect than the temperature. Though dynamic recrystallization occurs remarkably, the deformation textures are dominant in the hot-rolled microstructure. Increasing either the temperature or reduction ratio make the texture intensity enhance. After rolling, the yield strength (YS) of all samples is improved compared with as-homogenized state except for the sample rolled at 500 °C with 33% reduction. At the same rolling reductions, the increment in strength by increasing the rolling temperature is resulted from the combination of diminished Mg2Si precipitation and refined recrystallized grains. At the same rolling temperatures, the increment in strength by increasing the rolling reduction is mainly attributed to the high intensity of deformation texture and high density of dislocations retained in recrystallized grains.

Overcoming the ductility inadequacy while maintaining relatively high strength of Al Li alloys is in urgent need for developing new low-density and high-performance aerospace aluminum alloys. In this research, a warm multi-pass equal-channel angular pressing (ECAP) process was developed to simultaneously improve the strength and ductility of an Al-5.5Mg-1.6Li-0.1Zr alloy. The effects of the process on the microstructure evolution, plastic deformation and strengthening mechanism were also investigated. Results show that the ultimate strength (UTS) and elongation to failure (EL) of ultrafine-grained (UFG) alloy after 16 ECAP passes at 300 °C reach up to 476 MPa and 21.6% respectively, about 74% and 108% higher than those of the as-cast sample with coarse grains. The great improvement can be attributed to the coupling effect of the UFG microstructure and uniform distribution of large number of precipitates.

In the present work, an up-scaled rotational die equal channel angular pressing (RD-ECAP), which circumvented the limitation of the removing and re-inserting procedure of the conventional ECAP, was developed to make it possible to prepare large scale ECAP billets with dimension of 50 mm × 50 mm × 100 mm, and was successfully applied to an as-cast AZ91 alloy without a prior thermomechanical treatment. Benefiting from the large scale ECAP billet, the anisotropic tensile behavior of the ECAP alloy was examined, and was carefully linked to its microstructure and texture evolution. Our results shown that the large scale AZ91 RD-ECAP alloy exhibited simultaneously improved strength and ductility compared to as-cast alloy, while it possessed significantly anisotropic mechanical behavior. Interestingly, the anisotropy of ductility was nonsignificant, showing dramatically enhanced quasi-isotropic ductility. The improved strength and ductility were ascribed to the significant grain refinement, fine second phase, and texture strengthening. The tensile anisotropy was resulted by the bi-texture which was comprised of four prismatic texture components and three basal texture components. This study clearly highlights the potential for scaling RD-ECAP for an industrial scale implementation, while significant anisotropic mechanic behavior should be paid much attention.

A 0.31 mm-diameter Mg-6 wt% Zn alloy wire with high ultimate tensile strength of 300 MPa and elongation of 11% was successfully prepared via combination of extrusion, ECAP and hot drawing. Its excellent mechanical properties were attributed to the homogeneous and near single-phase microstructure.

Overcoming the toughness inadequacy of Al-Li alloys is in urgent need for developing new low-density and high-performance aerospace aluminum alloys. In this research, continuous equal-channel angular pressing (ECAP) and post-aging were developed to significantly enhance the impact toughness of 1420 Al-Li alloy. The effects of the processes on microstructure evolution, impact absorbed energy and fracture surfaces of 1420 alloy were investigated. The results demonstrated that the impact toughness of ultrafine-grained (UFG) 1420 alloy after 8 ECAP passes at 573 K reached up to 26.6 J/cm2 at room temperature and increased sixfold compared with that of the coarse-grained sample, but the post-aging reduced the beneficial effect. The remarkable improvement after the warm ECAP was mainly due to the UFG microstructure, certain amount of dislocations, and the fine precipitates with uniform distribution, thereby making UFG 1420 alloys more attractive in aerospace applications.

As a promising material for application in lightweight automobile, Al–Si alloys are subjected to complex cyclic thermo-mechanical loading when employed in engines. This study examined the high-cycle fatigue behavior of Al–12Si–4Cu-1.2Mn-T6 cast aluminum alloy at room temperature (RT) and 350 °C and evaluated the effect of different second phases by microstructure observation and nano-indentation characterization. The high-cycle fatigue strength of the studied alloy at RT and 350 °C is 125.0 MPa and 47.5 MPa, respectively, exhibiting excellent fatigue resistance compared with other heat-resistant Al alloys. Fatigue cracks originate from casting defects at RT, but nucleate from primary Al15Mn3Si2 phase on the specimen surface at 350 °C. The modulus difference between α-Al15Mn3Si2 and α-Al phases is higher at 350 °C than at RT, allowing cracks to initiate and propagate more likely along the phase interface at 350 °C. The hardness and reduced modulus of α-Al15Mn3Si2 phase are greatly higher at 350 °C than at RT, both in the suspended specimen and the fractured specimen. The significant difference in residual stress between α-Al15Mn3Si2 and α-Al phases indicates that α-Al15Mn3Si2 phase bears more stress loading than α-Al phase during fatigue process, especially at 350 °C. The findings presented in this study may shed some light on the design of high-performance heat-resistant aluminum alloys.

In this paper, the effect of the equal-channel-angular-pressed (ECAPed) substrate on the coating formation and anticorrosion performance of the anodized Al&ndash, 11Si alloy was systematically investigated. The ECAP process dramatically refines both Al and Si phases of the alloy. The parallel anodizing circuit is designed to enable a comparative study of anodizing process between the cast and the ECAPed alloys by tracking their respective anodizing current quota. The optimum coatings of both alloys were obtained after anodization for 30 min. The ECAPed alloy attained a thicker, more compact, and more uniform coating. Energetic crystal defects in the fine Al grains of the ECAPed substrate promote the anodizing reaction and lead to the thicker coating. Fragmented and uniformly distributed fine Si particles in the ECAPed alloy effectively suppress the coating cracks, enhancing the compactness of the coating. Overall, the ECAP-coated sample exhibits the best anticorrosion performance, which is evidenced by the concurrently enhanced prevention of coating and improved corrosion resistance of the substrate.

Mechanical properties usually take precedence for wrought magnesium alloy when it would be used as a structure material. This paper proposed an approach that achieved high strength in AZ91 Mg alloy. The main procedure combined solution heat treatment, equal channel angular pressing (ECAP), and the subsequent low temperature rolling. After solution heat treatment and ECAP, the alloy had fine grains and excellent ductility, which benefited the following rolling at low temperature. By the following rolling (at 150 &deg, C), the strength was further increased to ~432 MPa with a moderate ductility. This approach was proved effective in refining the grains and accumulating dislocations. The ultrahigh strength was attributed to the high density of dislocations and fine structure. The uniformly distributed fine precipitates also supplied precipitate hardening. Recrystallization that happened during rolling and annealing was the main reason for the moderate ductility.

Effect of trace addition of transition elements (Zr, V) on the flow behavior of near-eutectic Al–Si based alloys during hot compression was studied by Gleeble-3500 thermal simulator. Microstructure evolution was characterized by optical microscopy (OM), scanning electron microscope equipped with an electron backscattered diffraction (SEM/EBSD), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). Flow behavior shows that A8 alloy (with trace addition of Zr and V) is more sensitive to the deformation temperature and strain rate within a certain range. The activation energy of near-eutectic Al–Si alloy is greatly improved and dynamic recrystallization (DRX) is significantly inhibited at relatively high strain rate (≥ 1 s−1), due to micro alloying of Zr and V. The DRX processes of both A3 (without addition of Zr and V) and A8 alloys are discussed, emphasizing on the joint effect of micro-sized Si particles and nano-sized dispersoids.

Al Li alloys, as promising ultra-light airframe structural materials, have attracted extensive attention with respect to improving their mechanical properties. However, due to the detrimental effect of Li, the strength and ductility of Al-Mg-Li alloys have been found to be relatively low. In this work, high strength and simultaneously improved ductility were achieved in an Al-Mg-Li alloy with a high Li content by accurately controlling the microstructure through equal channel angular pressing (ECAP) and post-heat treatment. During the ECAP procedure, ultrafine grains with precipitating S1 phases were obtained in the alloy. Then, relatively coarse S1 phases due to the high Li content were effectively refined, large amounts of fine metastable δ’ phase particles uniformly precipitated without precipitate-free zones (PFZs), and ultrafine grains remained during subsequent heat treatment, thus achieving a combination of high strength (>450 MPa) and good ductility (>13.5%). The heat treatment including short-term solution and ageing after severe plastic deformation (SPD) was verified to be applicable to other Al Li alloys to adjust the ultrafine microstructure and achieve an optimal combination of strength and ductility, which can increase the applications of Al Li alloys for lightweight key components in the aerospace field

A high performance near eutectic Al–Si–Mg alloy profile is developed by micro alloying with 0.1wt.% Ti. The tensile properties of near eutectic Al–Si–Mg alloy with and without Ti in different processing conditions are tested for comparison. Microstructure evolution is observed by optical, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Results show that the yield strength (YS), ultimate tensile strength (UTS) and elongation of 0.1wt.% Ti alloyed A2 alloy reach up to 193 MPa, 296 MPa and 12.3% respectively, the tensile strength of which is about 50% higher than that of as-extruded base alloy and even stronger than that of the base alloy micro alloyed by 0.1wt.% Zr or 0.1wt.% V. Addition of 0.1wt.% Ti has obvious refine effect on the microstructure of as-cast Al–Si–Mg alloy, however, it has minor strengthening effect on the as-cast mechanical properties.

Atomistic simulation is applied to investigate the tension-compression (T-C) asymmetry of the nanotwinned Au nanowires (NTWs) with the different twin orientations in this paper. The result demonstrates that the T-C asymmetry is not only represented by the different yield stress under tensile and compressive load, namely yield asymmetry, but also highlighted by the different strengthening effect of twin boundaries, namely strengthening asymmetry. The yield asymmetry in the NTWs becomes weaker than that in their single-crystal counterparts and highly twin orientation-dependent. In more details, the compressive yield stress is larger than the tensile yield stress when the twin orientation angle is 0°, 19.47° and 90°, while the opposite is true as the twin orientation angle changes to 54.74°. The strengthening effect is much obvious under tensile load in the NTW with a twin orientation angle of 0°, while no significant difference is found in the NTW with a twin orientation angle of 90°. In contrast, the NTWs with a twin orientation angle of 19.47° and 54.74° exhibit great reduced tensile and compressive strength. This work not only deepens our understanding of the mechanical behavior of the nanotwinned metal but also provides a new strategy to control mechanical behavior via nanotwin boundaries design.

Although equal channel angular pressing (ECAP) effectively improves the mechanical properties of Mg alloys, it suffers from several problems, like complexity, being time-consuming, and being feasible for small sample sizes, which limit its potential application in industrial fields. Herein, we developed a compact processing route that combined industrial-scale ECAP with partial pre-homogenization and post-aging processes (rather than the commonly used full pre-homogenization and post-aging processes) to improve the processing efficiency. Using this compact processing route, we obtained an industrial-scale AZ91 ECAP alloy with a superior combination of high strength and good ductility. A multi-heterostructure with a heterogeneous grain structure and heterogeneous precipitates characterized the microstructure of this alloy. The heterogeneous grain structure comprised coarse grains and fine grains, and the heterogeneous precipitates included precipitate-dense grains and precipitate-sparse/free grains. The optimal mechanical properties stemmed from the simultaneous effects from the heterogeneous grain structure, heterogeneous precipitates, grain refinement, fine and dense γ-phase particles, and basal plane texture component. The present result highlights the impact of the initial second phase morphology and size on the microstructure evolution during subsequent ECAP or conventional thermo-mechanical treatments, which provides a new approach to control the microstructure of Mg alloys.

A high strength, good ductility and cost-effective Mg alloy is highly desirable for the light-weighting application. Here, a combined processing route of hot extrusion with multi-pass rotary die equal channel angular pressing (RD-ECAP) was applied to AZ91 Mg alloy with the aim of simultaneously improving its strength and ductility. The anisotropic mechanical behavior of the ECAP alloy was investigated in comparison to the extruded alloy. The evolution of the microstructure and deformation texture was further examined as a function of the ECAP pass to construct the microstructure/texture-anisotropic properties link. The results indicate that the ECAP alloy exhibits a simultaneous improvement in both strength and ductility along three orthotropic directions compared to the as-cast alloy, and more ECAP passes continue this improvement trend. Thus, the optimal mechanical properties with the yield strength of 214.3–279.9 MPa, the ultimate tensile strength of 321.0–382.0 MPa, and the elongation of 8.2–15.5% along three tensile directions are achieved in the ECAP alloy after 12 passes RD-ECAP. This also implies a considerable anisotropy in the ECAP alloy, but it is significantly weakened compared to the extruded alloy. Moreover, it is found that the low ECAP pass (4 passes) is enough to achieve a homogenous microstructure, which is characterized by the uniform and fine equiaxed grains (~7 μm) with the fine β precipitates (~1.5 μm) along the grain boundaries. Therefore, the initial extrusion can accelerate the grain refinement and microstructure homogenization in subsequent ECAP processing. Increasing the ECAP passes over 4, there are no discernible changes in the grain and precipitate microstructures, but the texture migration is observed. The high strength of the ECAP alloys not only stems from the well-known refinement strengthening, but also for texture strengthening. The contribution of the texture strengthening is enhanced with the increase of the ECAP pass.

Excellent ductility and high strength were achieved in the Mg-10.6Gd-2Ag (wt. %) alloy via an industrial-scale equal channel angular pressing (ECAP). The ECAP alloy exhibits an extremely high ductility (elongation of 22.6%) as well as a high strength (ultimate tensile strength of 417.2 MPa). This ductility exceeds the known ductility limit of the existing high-strength Mg-RE wrought alloys. After peak-aging, an optimal ultimate tensile strength of 460.3 MPa is obtained accompanied by a moderate ductility (elongation of 8.9%). The excellent ductility originates from the fine and full DRXed microstructure, which involves the homogenous and fine equiaxed grains, the cobblestone-like submicron particles distributed along the α-Mg grain boundaries, and the weak and approximately random texture. The submicron particles are identified as the dynamically precipitated Ag-containing Mg5Gd-typed compound. After peak-aging, co-existence of the high-density basal γ’’ plates and the relatively low-density prismatic β′ plates are observed in the α-Mg grain interior, and an interfacial phase is found to segregate in some α-Mg grain boundaries. The high strength is mainly ascribed to the synergistic effect of the fine grains, the high-frequency high angle boundaries, and the additional co-precipitates of the β′ plates and the γ’’ plates in the aged alloy.

The high temperature strengths of Al-5Cu-1Mn–xNi alloys as-cast, in T4 temper and in T6 temper were obtained by tensile test at 300 °C. Microstructure evolution was examined by optical microscope, SEM-EDS and TEM-EDS/SAD. The contributions to high temperature strengthening from three types of heat-resistant phases formed during solidification, solution treatment and ageing treatment respectively are discussed in this study and carefully gazed. It is found that the heat-resistant phases formed during solution treatment and during ageing treatment have much greater contribution to high temperature strengthening than that formed during solidification. Not consistent with the traditional realizations, can the θ′′ phase formed during ageing treatment in Al-Cu-Mn-Ni alloy act as a heat-resistant strengthening phase at high temperature. Thus, a new point of view is strongly confirmed that: strengthening the matrix by small dispersoid particles formed during solution treatment and by fine precipitates formed during ageing treatment should gain much more attention.

Developing high strength and high ductility magnesium alloys is an important issue for weight-reduction applications. In this work, we explored the feasibility of manipulating nanosized precipitates on LPSO-contained (long period stacking ordered phase) ultra-fine grained (UFG) magnesium alloy to obtain simultaneously improved strength and ductility. The effect of two aging treatments on microstructures and mechanical properties of an UFG Mg-10Y-6Gd-1.5Zn-0.5Zr alloy was systematically investigated and compared by a series of microstructure characterization techniques and tensile test. The results showed that nano &gamma, &rsquo, precipitates were successfully introduced in T5 peak aged alloy with no obvious increase in grain size. While T6 peak aging treatment stimulated the growth of &alpha, Mg grains to 4.3 &mu, m (fine grained, FG), together with the precipitation of &gamma, precipitates. Tensile tests revealed that both aging treatments remarkably improved the strengths but impaired the ductility slightly. The T5 peak aged alloy exhibited the optimum mechanical properties with ultimate strength of 431 MPa and elongation of 13.5%. This work provided a novel strategy to simultaneously improve the strength and ductility of magnesium alloys by integrating the intense precipitation strengthening with ductile LPSO-contained UFG/FG microstructure.

The present study investigated the effect of intermediate annealing temperatures on the microstructure, mechanical properties and conductivity of Al–0.2Mg–0.35Si–0.3Ce wire rod, which experienced hot extrusion (named as E), cold drawing (named as D), annealing (named as A) and cold drawing, i.e. EDAD. And four intermediate annealing temperatures (150, 200, 250, 300 °C) were carried out for investigation. Microstructure observation shows that no recrystallization occurs in the wire rod when annealed at 150 and 200 °C. However, it occurs when the annealing temperature reaches 250 °C. Tensile tests indicate that the ultimate tensile strength (UTS) of the as-EDAD samples firstly increases to a maximum value of 218 Mpa when the annealing temperature increased to 150 °C, and then decreases dramatically with the temperature continuously increasing. However, the elongation and conductivity of the as-EDAD samples just go oppositely. The conductivity of the sample annealed at 300 °C reaches 57.1%IACS, which is about 3.3%IACS higher than that of the sample without annealing. The effect of aging (190 °C for 20 h) on the mechanical properties and conductivity of as-EDAD samples was also investigated. Results show that the variation trend of UTS, elongation and conductivity of the EDAD-aging samples is similar to that without aging. The UTS decreases after aging, however, elongation and conductivity both increase.

Microstructure evolution of Al-0.35 wt.%Si-0.2 wt.%Mg-0.3 wt.%Ce alloy during hot extrusion and its contributions to mechanical properties and conductivity are investigated in this paper. Results show that, with a significant deformation (an extrusion ratio of 36), complete recrystallization occurs at the extrusion temperature ranging from 460 to 560 °C, and the grain size is increased only slightly with the temperature. However, when the rod is extruded at 510 °C with a small ratio of 16, only local and incomplete recrystallization occurs, and the grain structure is highly non-uniform. With the same large deformation (a ratio of 36), the rod extruded at 460 °C has the lowest strength. The severely occurred dynamic precipitation of Mg2Si phase is responsible for it. For the rod extruded at 510 °C with the small deformation (a ratio of 16), the highly non-uniform grain structure leads to a considerably reduction in all indexes of tensile properties. It is found that the conductivity of samples with the same ratio of 36 is decreased considerably with the extrusion temperature. The combined effects of the dynamic precipitation and lattice vacancy population on lattice distortion are responsible for it. In the rod extruded at 510 °C with the small ratio of 16, the retained large number of dislocations and sub-grains leads to a significant reduction in conductivity, compared to the one with the large ratio of 36. An excellent combination of strength and conductivity could be obtained by extruding at 510 °C with a ratio of 36. In this case, uniform and completely recrystallized grain structure is produced.

The hot deformation behaviors of three aluminum alloys containing different silicon contents (S1: Al–0.6 wt.% Si–0.5 wt.% Mg; S2: Al–7.0 wt.% Si–0.5 wt.% Mg; S3: Al–12.3 wt.% Si–0.5 wt.% Mg) were studied by hot compressive tests using a Gleebe-3500 thermal simulator. The compression tests were carried out in a temperature range of 573–773 K with strain rates of 0.01, 0.1, 1 and 5 s−1, and the true strain up to 0.6. The new developed constitutive equation incorporating the effect of strain on material constants has been constructed, and a five-order polynomial has been ascertained. High correlation coefficient suggests that it can be used to accurately predict the flow stress during hot deformation of Al–Si–Mg alloys with different Si contents. Due to impeding dislocation motion by a great amount of silicon particles, both S2 and S3 alloys have much higher state steady flow stress σ and deformation activation energy Q than S1 alloy. The differences in σ and Q between S2 and S3 alloys are thought to be due to the difference of recrystallization maturity during hot deformation. Based on the constructed processing maps, the instability domain area of S2 alloy with 7 wt.% Si is the largest among the studied alloys at the same strain. Due to much larger mushy zone of S2 alloy during solidification, the pore defects are prone to form in it that induces instability during hot deformation. It is also found that the strain has no considerable influence on the peak power dissipation efficiency during hot compression, but the effect of silicon content on it is not ignorable. In S2 and S3 alloys with high Si content, the peak power dissipation efficiency is less than that in S1 alloy, meaning that S2 and S3 alloys are more difficult to hot deformation than S1 alloy.