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Multilayered AZ91-(SiCP/AZ91) clad plates were fabricated at 300, 350 ℃ and 400 ℃ successfully by extrusion. The microstructure evolution, bonding interface and the mechanical properties of the AZ91-(SiCP/AZ91) clad plates were investigated in detail. The results show that grain of both of the AZ91 layer and SiCP/AZ91 layer are refined due to the dynamic recrystallization (DRX) during the extrusion processes and the SiCP/AZ91 layer processes much finer grain size. The SiCP distribution of SiCP/AZ91 layer is improved with increasing of extrusion temperature. No obvious delamination is observed in the AZ91-(SiCP/AZ91) clad plates fabricated at different temperatures. The metallurgical bonding of the interface between AZ91 and SiCP/AZ91 basically occurs in the extrusion die. The room-temperature strength of the AZ91-(SiCP/AZ91) composite lies between the AZ91 alloy and the SiCP/AZ91, corresponding well with the rule of mixture (ROM). The inadhesion of the SiCP in the SiCP/AZ91 layer is the main reason for the failure of the AZ91-(SiCP/AZ91) clad plates during tensile test.

The present research investigated the creep properties of the Mg-8Gd-2Y-0.5Zr alloys with different microstructures (as-cast, as-solution, T6 and as-extruded) after creeping at 200 ℃/70 MPa for 100 hours. Effects of the microstructures, including grain size, Mg5(Gd, Y) phase in cast alloy, β′ phase on creep properties were studied. The as-extruded alloy shows the worst creep resistance due to the refined grains caused by dynamic recrystallization resulting from the extrusion process. Although the Mg5(Gd, Y) phase located at the grain boundary can improve the creep properties of the cast alloy in the early stage creep, the precipitates of β′ phase in T6 alloy and those formed during the creep process in as-solution alloy, which can effectively inhibit the dislocation gliding, can be attributed as an important factor in improving the high temperature creep performance of the alloys. Consequently, the alloy after T6 treatment exhibited the lowest creep rate and the as-solution alloy possessed a better creep resistance than that of the cast alloy during the steady-state creep.

High strength intermediate modulus carbon fiber composites are still the main aviation composites in the world at present and for a long time to come. In recent year, based on the experience of high-strength carbon fiber composites, the industrialization technology of high strength intermediate modulus T800 grade carbon fiber have been broken through in China, and the resin matrix, prepreg and manufacturing process were analysized systematically for the high toughness composites reinforced by Chinese T800 grade carbon fiber. The impact resistance of the resin matrix composites reinforced by Chinese T800H grade carbon fiber is at the same level with that of foreign composites, and the hydrothermal resistance of high toughness epoxy resin matrix composites is better than that of foreign composites with the same CAI level. At the same time, the prepreg of Chinese T800H grade carbon fiber reinforced high toughness composites has excellent process ability, and it can meet the requirements of manual-layup, ATL and AFP. Based on the T800 grade composites, the main research goal is to improve the compression mechanical properties, elastic modulus and CAI based on BVID(barely visible impact damage) for high strength intermediate modulus carbon fiber composites in the future.

Objective To effectively use corn stover resources as animal feed, we explored the chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with lactic acid bacteria (LAB) and cellulase. Methods Corn ears including the cobs and shucks were harvested at the ripe stage. The corn stover was exposed in the field under natural weather conditions. Silages were prepared after 0, 2, 4, 7, 15, 30, and 60 d of exposure. Corn stover was chopped into approximately 1 to 2 cm lengths and then packed into 5 liter plastic silos. The ensiling density was 550.1±20.0 g/L of fresh matter, and the silos were kept at room temperature (10°C to 25°C). Silage treatments were designed as follows: without additives (control), with LAB, with cellulase, and with LAB+ cellulase. After 45 d of fermentation, the silos were opened for chemical composition, fermentation quality and in vitro digestion analyses. Results After harvest, corn stover contained 78.19% moisture, 9.01% crude protein (CP) and 64.54% neutral detergent fiber (NDF) on a dry matter (DM) basis. During field exposure, the DM, NDF, and acid detergent fiber (ADF) contents of corn stover increased, whereas the CP and water-soluble carbohydrate contents and in vitro digestibility of the DM and CP decreased (p

A microarc oxidation (MAO) coating was fabricated on the surface of TC4 alloy by adding SiC nano-particle into the base electrolyte. The influence of nanoparticles on the microstructure and corrosion behavior of MAO coatings was investigated. The results show that the introduction of SiC nanoparticles into the base electrolyte makes the coating thickness of MAO coating increased, from 9.2, 12.8, 12.4μm to 12.0, 14.9, 20.0μm, respectively, under the conditions of 550, 600V and 650V. The surface roughness of the coating (2.65, 3.34μm and 3.61μm) fabricated in SiC-containing solution increases with increasing the applied voltage. The introduction of SiC nanoparticles can effectively inhibit the microcracks in the coating, the coating thickness increase, and reduce the anodic current density, and thus the corrosion property of MAO coating increases. The OCP(open circuit potential) and corrosion potential increase by MAO coating.

Fragrant plantain lily (Hosta ventricosa) is an ornamental plant and widely cultivated in China due to its environmental adaptability. Here, the complete chloroplast genome of the H. ventricosa has been constructed from the Illumina sequencing data. The circular cp genome is 155,322 bp in size, and comprises a pair of inverted repeat (IR) regions of 24,912 bp each, a large single-copy (LSC) region of 84,113 bp, and a small single-copy (SSC) region of 20,782 bp. The total GC content is 38.0%, while the corresponding values of the LSC, SSC, and IR region are 36.2%, 32.5%, and 43.4%, respectively. The chloroplast genome contains 135 genes, including 88 protein-coding genes, 8 ribosomal RNA genes, and 39 transfer RNA genes. The neighbor-joining phylogenetic analysis showed a strong sister relationship with Hosta capitata in Hosta. Our findings provide a foundation for further investigation of chloroplast genome evolution in ornamental plant Hosta.

The tensile creep behavior of a Co-Al-W-base single crystal alloy containing Ta and Ti was investigated at 982 ∘C and 248 MPa. The lattice misfit of experimental alloy was measured to be positive by synchrotron X-ray diffraction at high temperature, and long term heat treatment at 1000 ∘C for 1000 h revealed a γ′ volume fraction of 75% without secondary phases. The creep test indicated that the creep properties of experimental alloy exceeded commercial 1st generation Ni-base single crystal superalloy CMSX-3 with respect to the rupture life. The initial cuboidal γ′ precipitates directionally coarsened parallel to the applied stress axis during the creep process. The stacking faults in {111} planes within γ′ rafts were the primary creep deformation mode by TEM investigation.