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This study aims to explore the development of business relationships from an interactional perspective, which challenges the conventional time-based view in Western contexts. Twenty in-depth interviews with Chinese SME managers reveal the uniqueness and importance of the operationalization of Confucian virtues, the guiding principles, and mechanisms for social interactions and trading practice, in developing Chinese business to business (B2B) relationship stages (i.e., discernment, authentication, stabilization, and decoupling). Given the role of Confucian virtues and their dynamics for the development of business relationships, we further argue that the evolution of a relationship depends on the shifts in concerns of transactional and relational governances among business partners. Our propositions advance the literature by showing that distinct constructions of Confucian virtues mark a vantage point for business operators and practitioners in formulating effective B2B relationship strategies in China, and raising future research questions of the impacts from sub-evolutions in Confucian virtues on B2B relationships.

The effect of short-time heat treatment on the microstructure and mechanical properties of a joint welded by friction stir welding (FSW) was investigated in a 7075 Al alloy. Short-time post-solution and aging treatment promoted recrystallization in the thermal–mechanical affect zone and did not lead to severe grain coarsening in the nugget zone (NZ) of the FSW joint. Solution treatment for 10 min and subsequent aging treatment for 3 h led to the precipitation of high-density η′ phases in the FSW joint. Short-time post-solution and aging treatment enhanced the hardness of HAZ and NZ of the FSW joint and improved the strength of this joint. The yield strength of the FSW joint after solution and aging treatments reached 465 MPa, and its welding efficiency was 89.2%.

Post-heat treatment was conducted on the Al-Zn-Mg-Cu-Sc-Zr alloy treated by friction stir processing (FSP) to optimize its strength and corrosion resistance. Different post-heat routes had significant bearing on the phase composition of the FSP sample, while its fine equiaxed grain structure could be retained during post heating. Enhanced strength of the FSP sample was obtained by post-heat treatments. The FSP sample after T6 treatment (artificial aging to peak hardness value after solid solution treatment) exhibited the highest strength in virtue of its high precipitation strengthening effect, and the high ductility of the FSP sample could be retained after solid solution treatment. Furthermore, the FSP sample presented better corrosion resistance after artificial aging and T6 treatment by reducing its solution atom numbers.

Summary Background Vibration is commonly used to relax tension in the limb and truck muscle. Vibration used directly on the muscle concerned and vertical vibration used on the whole-body through a foot platform have been reported in the literature to be useful to release muscle tension. Aim The present study investigated the effect of indirect whole-body vibration (WBV) and direct localized perilaryngeal vibration (LPV) on the phonatory functions of nondysphonic individuals with vocal fatigue. Methods Forty-four subjects (mean age = 21.67 years) with normal voice, were randomly assigned to either the WBV group, the LPV group, or the Control (sham hand-held vibratory device) group. They performed karaoke singing for at least 95 minutes. They then received either WBV through a Turbosonic vibratory machine, LPV with a Novofan vibrator, or a sham vibrator for 10 minutes. The highest pitch produced, and self-reported vocal fatigue score were taken before singing, after singing, and after the intervention. Data were analyzed separately for the gender subgroups. Results All subject groups showed significant reduction of vocal function (highest pitch production, and vocal fatigue score) after singing. Following the vibrational interventions, both the WBV and LPV groups showed significantly recovery in the highest pitch production and the perception of vocal fatigue (P Conclusion Vibrational therapy, whether it is localized vibration on the peri-laryngeal muscles, or whole-body vibration, is more effective than voice rest per se in relieving vocal fatigue. Vibrational methods are recommended for treating vocal fatigue.

The calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) complex is an essential calcium sensor and contributes to biotic and abiotic stress responses. However, citrus CBL and CIPK gene family members and their underlying roles during drought and arbuscular mycorrhizal fungi (AMF) colonization remain relatively unknown. In the present study, CBLs and CIPKs were characterized in Citrus sinensis by analyzing the presence of specific domains such as the elongation factor (EF)-hand motif in CBLs, and a protein kinase and an Asn-Ala-Phe domain in CIPKs. After mining the C. sinensis genome, we identified 8 CsCBLs and 17 CsCIPKs. Among these genes, three CsCBLs and nine CsCIPKs showed syntenic relationships with the Arabidopsis thaliana homologs AtCBLs and AtCIPKs, respectively. According to gene expression and cis-acting element analysis, all 8 CsCBLs and 16 CsCIPKs were expressed in the roots, where the regulation of expression was not consistent with their promoter cis-elements. Drought treatment remarkably downregulated the expression of CsCBL8 and upregulated CsCBL7, CsCIPK4, and CsCIPK7 expressions. The AMF colonization induced CsCBL4, 5, 6, and 7 as well as CsCIPK2, 4, 10, 11, 13, 14, and 16 expressions and repressed CsCBL1, 2, 3, and 8 and CsCIPK1, 3, 6, 8, 9, and 12 expressions. Based on the expression data and co-expression analysis, CsCBL1-CsCIPK1, CsCBL1-CsCIPK3, CsCBL1-CsCIPK6, and CsCBL1-CsCIPK9 showed the significant positive correlations to drought and AMF responses.

Al-Zn-Mg-Sc alloys with different grain structures were fabricated using friction stir processing (FSP) and rolling with different routes. The hot rolling (HR) sample after T6 treatment exhibited stronger texture than the other three samples, and the T6 FSP samples exhibited the finest grains, with average grain size (AGS) of 5 μm. Cold or hot rolling before T6 treatment led to grain coarsening in the T6 FSP samples, and the AGS in the T6 FSP + HR reached 126 μm. All the samples exhibited a low density of dislocations and contained coarse grain boundary precipitates, Al3(Sc,Zr) phases, and a high density of η′ phase. The T6 HR sample exhibited the highest strength mainly due to its strong texture and reasonable grains size, and the T6 FSP sample exhibited the highest ductility due to its fine equiaxed grain structure, which can promote the redistribution of stresses and prevent strain localization during the tension process.

Al–Mg–Si alloys with different heat treatment states were used as base metals (BMs) in investigating the effect of BM state on the microstructure and mechanical properties of Al–Mg–Si alloy friction stir-welded (FSW) joints. The Al grains and insoluble phases of the FSW joints were not affected by BM state, but the compositions of the precipitated phases in the heat-affected zones (HAZs) and nugget zones (NZs) depended on the phase compositions of the BMs. The FSW joint that was welded using the BM with water quenching (WQ) and artificial aging state exhibited the greatest hardness among the joints at the same zones because of the high densities of the β″ phases in the BM, the fine and high densities of the β′ phases in the HAZ, the high number of solution atoms, and the formation of Guinier–Preston zones in the NZ. Moreover, the joint exhibited the highest yield strength because of the high hardness of its HAZ, which is the fracture location in FSW joints. The FSW joint that was welded using the BM with WQ and natural aging state exhibited the highest ultimate tensile strength and tensile elongation because of its high structural uniformity.

In this study, 7xxx (Al-Zn-Mg-Cu) alloys with high Zn concentrations were fabricated by increasing the Zn contents of 7085 Al alloys. The hardness, quench sensitivity, and electrical conductivity of the alloys and a 7085 Al alloy under peak-aged state were studied. The high Zn concentration alloys had higher η′ phase densities and lower quantities of Mg solid atoms than the 7085 Al alloy and thus exhibited higher hardness and electrical conductivity. The high Zn concentration alloys also exhibited slightly higher quench sensitivity than 7085 Al alloy, and the depth of the quenching layer of the alloy with 11.27 wt% Zn content reached 100 mm. This work confirmed that the novel 7xxx alloy with high Zn concentration showed balanced performance, exhibiting enhanced hardness and conductivity and reasonable quench sensitivity compared with the 7085 commercial Al alloy.

The effects of Sc and Zr microalloying on the microstructure and mechanical properties of a 7xxx Al alloy with high Cu content (7055) during casting, deformation, and heat treatment were investigated. The addition of Sc and Zr not only refined the grains but also transformed the θ-phase into the W-phase in the 7055 alloy. Minor Sc and Zr additions enhanced the hardness and yield strength of the 7055-T6 alloy by strengthening the grain boundaries and Al3(Sc,Zr) precipitates. However, a further increase in the Sc and Zr fractions did not refine the grains but instead resulted in the formation of the large-sized W-phase and primary coarse Al3(Sc,Zr) phase and subsequently deteriorated the mechanical properties of the alloys. The 7055 alloy with 0.25Sc addition exhibited the best mechanical property among the prepared alloys.

This study investigated the microstructure, mechanical, and damping properties of a non-age-hardened Al alloy (5086) and an age-hardened Al alloy (7075) after friction stir processing (FSP). Microstructural analyses indicate that FSP led the grain refinement of samples, and the grains size decreased with the decrease in the tool rotation rate. Furthermore, FSP with low rotation rate promotes the η phase precipitation in the 7075 alloy, causing the micron-sized particles in the 5086 alloy to break up. After being subjected to FSP with low rotation rate, the 5086 and 7075 alloys exhibited excellent mechanical and damping properties. Such improved properties were ascribed to their equilibrium grain boundaries, fine grain, low density of dislocations, high fraction of high misorientation angle, and uniform particle distribution.

To reduce the computational requirements of full multidimensional numerical calculations for silencers with arbitrary but uniform cross sections, a semi-weak-form mesh-free method (MFM) that combines the axial and transversal solutions of the wave equation is developed. Because perforated tube silencers contain more Neumann boundaries than other silencers, the transversal modes are extracted using the weak-form MFM, which is based on the radial basis function point interpolation method (RPIM) for creating shape functions and the Galerkin method for obtaining the weak formulation of transversal governing equations, as well as the Gauss integration scheme for computing the system matrices. The mode-matching approach employs the modal expansion of transversal modes and then matches the sound pressure and particle velocity at the cross sections to predict the transmission loss (TL). Several test cases are presented to validate the computational accuracy and efficiency of the proposed combined technique. Additionally, the stability and efficiency of the weak-form and strong-form MFMs are compared.

Friction stir processing (FSP) was conducted on an Al-Si casting alloy. The Si phase and Al grains of an Al-Si casting alloy were refined through FSP. Furthermore, FSP with high rotation rate led to the precipitation of Mg and Si atoms and the formation of Mg2Si phase in the Al-Si alloy. Precipitation improved the low-strain damping capacity but deteriorates high-strain damping capacity of the FSP sample at room temperature. At low rotation rate, the FSP sample exhibited excellent high-temperature damping capacity mainly because of its fine grain structure and the low density of its pinning points. The plastic instability of the Al-Si alloy was eliminated by FSP because of the refinement of the Si phase. The increase in the strength of each FSP sample was attributed to the increase in second-phase and boundary strengthening effects. Thus, the mechanical properties and damping capacity of Al-Si were enhanced after FSP.

This study investigated the effect of 0.25 wt% Sc addition on the microstructure and mechanical properties of AA 7055 alloy. The addition of Sc obviously refined the grains of AA 7055 alloy during casting, homogenizing, rolling, solution, and aging treatments due to the formation of primary and precipitate Al3(Sc,Zr) phase. The recrystallization and precipitation of AA 7055 alloy were inhibited during heat treatments by Sc addition. The Sc-containing AA 7055 alloy exhibited higher thermal stability than AA 7055 alloy during homogenizing treatment, because of the grain boundary pinning effect of nano-sized Al3(Sc,Zr) particles. Given its structure characteristics such as fine grains, fine η′ phase, and less η phase, AA 7055 alloy with added Sc showed good mechanical properties after aging at 120 °C for 24 h, with an ultimate tensile strength (UTS) of 679 MPa and elongation (EL) of 14%. This work provides an effective strategy to fabricate Al–Zn–Mg(–Cu) series (7xxx) alloys with excellent mechanical properties.

Sc addition, friction stir processing (FSP), and subsequent solid-solution treatment and aging to peak hardness (T6 treatment) were applied on a 7055 Al alloy. Fine equiaxed grains were obtained after FSP, and the size of the grains was further refined by minor Sc addition. Subsequent solid-solution treatment led to the dissolution of η phase, and aging led to the precipitation of η′ phase in the FSP samples. The Al3(Sc,Zr) particles effectively inhibited the grain coarsening in the Sc-containing FSP sample during the T6 process. Thus, a high density of η′ phase and a fine equiaxed grain structure were obtained in the Sc-containing 7055 alloy after FSP and T6 treatment. The special structure endowed this alloy with higher yield strength than the T6 treated 7055 alloy. FSP enhanced the high-temperature internal friction value of the Sc-containing 7055 alloy, and subsequent T6 treatment did not significantly reduce the value. The Sc-containing 7055 alloy exhibited greater high-temperature internal friction value than the T6 samples and the 7055 alloy fabricated using the same processing route.

In East Asians, a common method to ameliorate puffy eyelids is to resect the excess orbital fat and the orbicularis. However, in some patients, a satisfactory improvement cannot be achieved because of the thick submuscular fibroadipose tissue (SMFAT) and minimal orbital fat. The SMFAT lies between the orbicularis and the orbital septum and can also be found in the pretarsal area. It is responsible for puffy eyelids and the slackening of the tissue after removal. In this study, we combined an extended SMFAT resection with the ladder suture technique to correct puffy SMFAT eyelids.A total of 76 patients with a thick SMFAT and minimal orbital fat were recruited. The thick SMFAT, which included the soft tissue near the artificial fold and the pretarsal area soft tissue, was resected. The ladder suture technique was performed by positioning the stitch 1 mm below the orbicularis margin after a skin flap margin puncture. The esthetic effect was evaluated pre-operatively and at 12 months post-operatively.The pre-operative thickness of the SMFAT and full layers of the eyelid were 0.27 ± 0.03 mm and 2.01 ± 0.11 mm, respectively. One year after surgery, the thickness was 0.08 ± 0.02 mm and 1.68 ± 0.14 mm, respectively (p0.05). The post-operative upper eyelash lift-up angle and the eyelash exposure length were significantly increased on both sides compared with the pre-surgery (p0.05). No patients experienced complications.An extended SMFAT resection combined with the ladder suture technique can effectively correct puffy SMFAT eyelids without complications.

Auger recombination, a process closely related to the device reliability, of a working 2 µm InGaSb/AlGaAsSb quantum well (QW) laser is first investigated via measuring its spontaneous emission. By extracting and analyzing the Z power parameter, severe Auger recombination at relatively low current density/carrier density of GaSb-based lasers has been experimentally revealed.

The corrosion behavior of nickel-based UNS N10003 alloy with different yttrium contents in molten fluoride salt environment was investigated. The results showed that after an 800 oC/1000 h corrosion test, the alloy contained 0.05% yttrium experienced the least weight loss than other alloys without/with higher yttrium contents. Microstructure, surface micro-chemistry analysis indicated that a YF3 and Y2O3 mixed layer formed in the near surface region for this specific alloy. The retardation of active element dissolution because of the present of YF3 was suggested to be the main reason for its superior corrosion resistance in the molten salt environment.

The microstructure and mechanical properties of (Zr-Ti)1-χNiχ(χ =0, 1, 3, and 5 wt.%) alloys were studied. With the addition of nickel (Ni), the phase composition of alloys changes from α phase to α phase + hexagonal close packed (hcp) C14 Laves-phase. The thickness of lamellar α phase decreases with increasing Ni content. Optical microscopy and transmission electron microscopy results indicated that C14 Laves-phase is formed on the boundary. The Zr-Ti-3wt.%Ni alloys exhibits better ultimate compressive strength and compressive plasticity (1715 MPa and 9.70%) than that of Zr-Ti alloys (1598 MPa and 12.40%). The decrease of the average thickness of the lamellar α-phases (from 0.183 μm to 0.065 μm) leads to the improvement of the strength of the alloy. Additionally, the solid solution strengthening and the second phase strengthening are also important reasons for the improvement of the strength.

Al-35Zn and Al-35Zn-0.5Sc alloys were fabricated in this study. The addition of 0.5 Sc promoted the grain refinement of the Al-35Zn alloys during solidification, heat treatment, and hot rolling. Dynamic precipitation also occurred in the Al-35Zn and Al-35Zn-0.5Sc alloys during rolling. The damping capacity and mechanical properties of the Al-35Zn alloy were improved by the Sc addition and hot rolling. The rolled Al-35Zn-0.5Sc alloy with 90% reduction demonstrated better damping capacity than those of commercial Al alloys and some metallic materials with high damping capacity, which is mainly attributed to the high interface sliding capacity. Compared with the commercial Al alloys, the rolled Al-35Zn-0.5Sc alloy with 90% reduction showed balanced mechanical properties, including high strength and reasonable ductility. This work provided an effective strategy for preparing Al alloys with excellent damping capacity and mechanical properties.

The effects of Sc addition and pre-aging on the microstructure and mechanical properties of friction stir processed (FSP) 7055 Al alloy were investigated. The addition of Sc effectively inhibited the coarsening of grains in the FSP 7055 Al alloy due to the grain boundary pinning effect of Al3(Sc,Zr) particles. The high density of Al3(Sc,Zr) particles also provided more preferential nucleation sites for the precipitation of the η phase during FSP, and then inhibited the coarsening and increased the density of the η phase in the FSP 7055 alloy. The η′ phase precipitated in the 7055 and Sc-containing 7055 during artificial aging, and then dissolved into the Al matrix during FSP. Thus, pre-aging effectively inhibited the formation of the η phase during FSP, and increased the quantity of the solute atoms in the FSP samples. The mechanical properties of the FSP 7055 Al alloy were improved by the addition of Sc and pre-aging. The aged 7055–0.25Sc Al alloy with FSP showed the highest ultimate tensile strength of 578 MPa; and the aged 7055 Al alloy with FSP showed the largest elongation of 21%. This work provides an effective strategy to improve the mechanical properties of FSP Al alloys.

Friction stir processing (FSP) was performed on both age-hardened and non-age-hardened Al alloys, with excellent damping properties obtained. The improved room temperature damping capacity of the FSP Al alloys can be mainly attributed to their low amount of solute atoms and the uniform distribution and high density of incoherent phases. The FSP Al alloys also exhibited improved high temperature damping capacity due to their equiaxed grain structure. The grain refinement and grain boundary pinning phase can further optimize the damping property of the FSP Al alloys. This work provides an effective strategy to improve the damping capacity of commercial Al alloys, which are regarded as low damping materials.

In this study, the ultrafine grained (UFG) 6061 Al alloys fabricated by cold rolling were friction stir welded (FSW) with different rotation rates under both air cooling and rapid cooling in water. Low-heat-input parameters of 400 rpm rotation rate in water (400-Water) could effectively inhibit the coarsening of recrystallized grains, reduce the precipitation rate, and retain more dislocations of the UFG 6061 Al parent metal. 400-Water joint showed high lowest-hardness value, narrow low-hardness zone, and high tensile strength, attributing to the effect of dislocation, grain boundary, solid-solution, and precipitation hardening. This work provides an effective strategy to fabricate large-sized bulk UFG Al alloy by cold rolling with large deformation and low-heat-input FSW.

This study investigated the effects of 0.25% (mass ratio) Sc addition on the microstructure and mechanical properties of 7055 alloy during aging. Sc addition induced a grain boundary effect, which refined the grains of the 7055 alloy. Sc addition also increased the precipitation nucleation efficiency and promoted the uniform precipitation of the η′ phase of 7055 alloy during aging. Compared with pure 7055 alloy, 7055 alloy with Sc exhibited improved hardness, tensile strength, ductility, and thermal stability. This improvement was attributed to the finer size, higher density, more uniformly distributed η′ phase, less η phase, and finer Al grains of 7055 alloy with Sc compared with those of 7055 alloy without Sc.

This study investigated the effects of friction stir processing (FSP) and addition of 0.25% (mass ratio) Sc on the microstructure, mechanical properties, and damping capacity of AA 7055 alloy. Microstructure analyses revealed that a low tool rotation rate of 300 rpm effectively inhibited the grain coarsening in the recrystallization of the alloy during FSP. Sc addition prevented the coarsening of grains and precipitated η phase and the annihilation of dislocations in the FSP AA 7055 alloy. After being subjected to FSP at 300 rpm, the AA 7055 alloy containing Sc exhibited good mechanical and damping properties, which were mainly attributed to the fine recrystallized grain structure, fine precipitated η phase, and large number of nano-sized Al3(Sc, Zr) particles located at the grain boundaries and dislocations. This work provides an effective strategy for preparing commercial Al alloys with excellent damping capacity and mechanical properties.

The Al particle reinforced 7075 Al matrix composites with the layered structure are prepared by hot rolling to improve the damping property of the alloy. Numerous interparticle interfaces are observed in the Al particle layer (reinforcement), and the traces of no interfacial reaction or elemental diffusion are found between the matrix and reinforcement layer. The tensile strength of the composite is 29% higher than that of the matrix. The internal friction values of the Alp/7075Al lamellar composite and the 7075 Al matrix are found to increase with the increase in temperature and strain, respectively. At 570 K, the internal friction values of the composites are found to be as high as 0.105, which is 337% higher than that of the matrix, and an internal friction peak (P2) appears in the composites due to the recrystallization of Al particles at high temperature. The comprehensive damping index of the composite is found to be about 2.9-fold of the 7075 Al matrix. The damping mechanism of the composite is mainly attributed to dislocation damping, grain boundary damping, and interface damping.

The effect of long-time thermal aging on corrosion behavior of type 316H stainless steel in molten chloride salt was studied. The results showed the long-time aging at 700 °C promoted the precipitation of both M23C6 carbide (dominant) and η phase at the grain boundaries and within the grains. Post-corrosion characterization showed the thermally-aged 316H experienced ~23% less weight loss than the as-received 316H and the Cr depleted region in the thermally-aged 316H was also much thinner than the as-received one. The mechanisms responsible for the different corrosion behaviors of the specimens were discussed based on the experimental observation.

The AlSi30p/5052Al composite with porous particle layer was successfully produced by hot rolling. Numerous interparticle interfaces and pores were seen in the particle layer. The dynamic mechanical analysis shows that the internal friction and the storage modulus of the composites are higher than that of the matrix. Due to the presence of an intermediate particle layer, dislocation and residual internal stress increase in the composites, and thereby improve the storage modulus of the composites. The comprehensive damping index of the composites is better than that of the matrix. The synergistic damping effect caused by the porous structure and a large number of interfaces between particles in the particle layer improve the damping capacity of the composites.

The corrosion behavior of a novel low Cr content Laves phase strengthened wear-resistant alloy (Co-27.3Mo-2.9Cr-3.1Si) in molten FLiNaK salt (LiF–NaF–KF: 46.5–11.5–42 mol.%) was investigated by static immersion test at 700 °C. The microstructure and phase composition of the alloy after corrosion were characterized by scanning electron microscopy (SEM), electron probe micro-analysis (EPMA) and transmission electron microscopy with energy dispersive spectrometry (TEM/EDS). Results show that the alloy surface exhibit either pitted or roughened morphology after corrosion. The preferential corrosion of the Laves phase contributes to the pitting, whereas the formation of Co3Mo particles and Co layers contributes to the roughening. Carburization occurs in both the Laves phase and alloy matrix in the corrosion affected zone, forming Co3Mo3C carbides of different sizes. In addition, the thermal exposure effect during corrosion causes phase transformation in the entire alloy matrix and form Co3Mo stripes. The observed non-uniform corrosion is mainly induced by the trace amount of H2O in the salt, and it suggests that the corrosion resistance of the alloy is not satisfying in the test condition.

Al–Si–Mg alloys with 7% and 12% (mass ratio) Si contents were subjected to friction stir processing (FSP), warm rolling (WR), and heat treatment. The effects of process routes on the microstructure and mechanical properties of the Al–Si–Mg alloys were studied. FSP could break the eutectic structure and lead to the uniform distribution of the generated fine Si particles in the two Al–Si–Mg alloys. WR could effectively decrease the porosity of the Al–Si–Mg alloys. T6 could lead to the precipitation of the β'′ phases in these alloys. The structure characteristics, including fine grain and second phases, uniformly distributed Si particles, high density of β'′ phases, and low porosity, resulted in the satisfactory mechanical properties of the Al–Si–Mg alloys after FSP, WR, and T6 treatments.

A coupled method (abbreviated here as the MFMM method) that combines the mesh free (MF) method and mode matching (MM) approach is introduced to predict the transmission loss (TL) of expansion chamber silencers. The Hermite radial point interpolation collocation (HRPIC) method is employed to solve the 2-D eigen equation of silencer sections. Then the mode matching method is used to calculate the transmission loss. The eigenvalues predictions of circular cross section from the present method exhibit desirable precision comparison with analytical results. Additionally, the effects of size of influence domain, number of computational nodes and shape parameters of radial basis functions on the calculation accuracy are evaluated. TL calculations of four typical expansion chambers with extended inlet and outlet are presented to valid the computational accuracy and efficiency of the proposed combined method.

In this study, rolling was performed on a binary Al–35Zn alloy. The grain refinement and dynamic precipitation were obtained in the rolled samples. The nano-sized Zn phase with a rod-like shape was obtained in the hot rolled sample, whereas the precipitated Zn phases were coarsened to hundreds nanometer with an equiaxed shape and located at the triple junctions of the Al grains after cold rolling. The cold rolled sample exhibited excellent damping capacity, mainly attributed to the special microstructure characterized by fine grains, low solid solubility, and wetting interface between Al and Zn phases. Furthermore, the cold rolled sample showed a ductile fracture and high ultimate tensile strength, with the main strengthening mechanisms being dislocation and boundary strengthening. The hot rolled sample with 90% reduction showed balanced mechanical properties, including high strength and reasonable ductility. This work provided an effective strategy of preparing Al alloys with excellent damping capacity and mechanical properties.

In this study, friction stir processing (FSP) was performed on an Al-Mg-Si alloy (AA 6082-T4) at a low tool rotation rate of 200 rpm, and good mechanical and damping properties were simultaneously obtained after FSP. The combination of excellent ductility, moderate strength and excellent room/high temperature damping capability at FSP sample was attributed to the ultrafine recrystallized grains with predominant high-angle grain boundaries and moderate dissolution of metastable phases, and the fragmentation of micron-sized second phase during FSP. This work provided an effective strategy to improve the damping capacity of commercial Al alloys without sacrificing their mechanical properties.

Binary Al-Zn alloys with different Zn contents were fabricated by casting and heat treatment. Analysis of mechanical properties showed that the hardness and tensile strength of Al-Zn alloys increased with increased Zn content, with the post-heat treatment hardness and ultimate tensile strength of Al-49Zn alloy reaching as high as 152 HV and 330 MPa, respectively. Meanwhile, the plasticity and toughness of Al-Zn alloys decreased with increased Zn content. Solid-solution strengthening was the main strengthening mechanism for Al-Zn alloys, and Orowan strengthening was also observed in Al-49Zn alloy. The fracture mode of Al-20Zn and Al-35Zn alloys was ductile, whereas Al-20Zn alloy showed good impact toughness. This work provided a basis for further improving the cast component design of the Al-Zn-X system.

Sc addition and rolling were performed to optimize the mechanical properties of Al alloys with high Zn concentrations. The addition of 0.5 Sc reduced the grain size of the Al–35Zn alloys during solidification, heat treatment, and rolling. Nanosized, rod-shaped Zn particles dynamically precipitated from the Al lattice during hot rolling and consequently coarsened during further cold rolling. Following 50% hot rolling and 80% cold rolling, Al–35Zn–0.5Sc alloy demonstrated the highest strength, i.e., an ultimate tensile strength (UTS) of 482 MPa. Moreover, following 90% hot rolling, Al–35Zn–0.5Sc alloy demonstrated balanced mechanical properties including high strength and reasonable ductility (UTS and tensile elongation of 430 MPa and 10%, respectively). This work provided an effective strategy to fabricate Al alloys with high Zn concentrations and excellent mechanical properties.

A novel ventilated shaft brake disc prepared by SiC 3D /Al alloy co-continuous composites (SiC 3D /Al, 3D means three-dimensional network structure) was presented in this study, which can effectively reduce the unspring weight of high-speed trains. The innovative concept is based on the use of a high temperature and low wear SiC foam material fill with a metal alloy, able either to improve friction and wear properties and to transmit, with a very high flow rate, the heat produced on the friction surface. In order to identify the geometric design and used material of this brake disc and secure braking stability, the numerical thermal and thermal stress investigations considering air cooling during emergency braking phase at the speed of 350 km/h were carried out using finite element (FE) and computational fluid dynamics (CFD) methods. The results showed that low temperature was obtained, as well as distributed uniformly on the brake disc, which attributes to high thermal conductivity of the disc material together with excellent cooling ability of the brake disc. During the braking phase, maximum thermal stress is 186.44 MPa, at 30 s, but the highest temperature is 471.08 °C, at 70 s, they behaved inconsistently in time. The maximum thermal stress is lower than the permitted stress of the disc material. The simulation results are consistent with the experimental dates well. The brake disc can meet the requirement of high-speed trains at 350 km/h.