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Three AIEE-active V-shaped fused-biscoumarin derivatives were prepared and their potential for application in OLED was explored.

Al-Si casting alloys are the most commonly used materials for piston alloys. The coefficient of thermal expansion is the key property of a piston material for improving the overall performance and service life of an engine. In the present study, the relationship between the morphology of the excess silicon phase and the coefficient of thermal expansion of Al-Si binary casting alloys was discussed. Optical and scanning electron microscopy were utilized to observe the morphology of the excess silicon phase in the Al-Si binary casting alloys before and after solution aging treatment. The results showed that the morphology of the excess silicon phase significantly influenced the coefficient of thermal expansion of the Al-Si binary casting alloys. After solution aging treatment, the coefficient of thermal expansion of the Al-Si binary casting alloys increased due to the rounding and granulating of the excess silicon phase precipitated during the casting process and decreased due to the precipitation of the finely dispersed Si phase in the α-Al matrix. The change in the coefficient of thermal expansion depended on which of the two kinds of morphological transformation of the excess silicon phase is dominant.

In albino tea cultivars, the content of chlorophyll, carotenoids and metabolites changes significantly, which has an important influence on the regulation mechanism of tea albinism. Albino tea mutants with specific shoot colors (white or yellow) have received extensive attention for their uniqueness. Herein, novel natural mutants of C. sinensis ‘Fuyun 6’ with yellow leaves (YF-6) and the same genetic background as the original green variety (GF-6) were obtained. The metabolomes of the two species were compared using LC–ESI–MS/MS. A total of 124 significantly changed metabolites (SCMs) were identified in the metabolite profile of YF-6. Compared with GF-6, 64 upregulated metabolites and 60 downregulated metabolites were identified in YF-6. Functional enrichment analysis showed that the differential metabolites were mainly enriched in flavonoid biosynthesis pathway. Moreover, metabolites related to carbon and nitrogen metabolism were enriched in other secondary metabolic pathways. The chlorophyll content in YF-6 was significantly reduced, and the carotenoid content was slightly decreased. A large number of metabolites related to photoprotection accumulated in YF-6, including flavonoids, l-ascorbic acid, lipids, and vitamins and their derivatives. The decrease in chlorophyll content increases the possibility of light stress, thereby facilitating large-scale metabolic reprogramming events under light pressure. This study provides a reference value for further research on the metabolic mechanism of albino tea germplasm and provides new materials for the production and application of tea.

Iron-based alloy coatings were deposited on grey cast iron through plasma transfer arc welding. Results showed that the iron-based alloy coatings are composed of pearlite, martensite, austenite, an...

The Al-Si-Cu-Mg-Ni alloy is a commonly used piston alloy. In this work, different amounts of phosphorus modifier and Al-2P (Al-2%P) master alloy modifier were added to the original alloy. The ultra...

The effect of diamond surface pretreatment and content on the microstructure and mechanical properties of NiAl/Fe–x diamond (x=0,5,10,15,and 20 wt.%) alloys was investigated after mechanical alloying with subsequent hot-pressing sintering. The results showed that after the surface pretreatment, a complete transition layer containing W existed on the outer surface of the diamond grains, which improved the interfacial bonding strength of the diamond grains and NiAl/Fe matrix to an excellent level. As the diamond content increased, the compressive strength of the NiAl/Fe-based alloys declined, but the alloy with 10 wt.% diamond had a higher value than that of the other NiAl/Fe-based alloys. Short cracks and transgranular fracture were observed in the fracture surface of all materials. For the material with 20 wt.% diamond, intergranular fracture was obvious, and many diamond particles appeared along the fracture direction, which caused the compressive strength to be the lowest of the samples considered in this study. After the addition of diamond, the oxidation resistance of NiAl/Fe-based alloys decreased due to a loose oxidation layer and diamond graphitization. The thermal conductivity of the alloy first increased and then decreased with increasing diamond content. A NiAl/Fe-based alloy with 15 wt.% diamond demonstrated the maximum thermal conductivity of 53.2 W/(m·k) at 600°C among the samples in this study.

Blast-furnace slag is one of the main by-products produced in the process of blast-furnace ironmaking. Its metallurgical properties have an important impact on the smooth operation and long life of blast furnaces. In this paper, the activity of MgO in a CaO-SiO2-MgO-Al2O3 quaternary slag system was measured using the reference-slag method at 1773–1873 K. The effects of temperature on MgO activity and the activity coefficient of Mg in Sn of the CaO-SiO2-MgO-Al2O3 quaternary slag system were discussed. The results showed that when w(MgO)/w(Al2O3) = 0.40, B(w(CaO)/w(SiO2)) = 1.30 and w(Al2O3) = (12 %; 15 %; 18 %; 20 %), the activity of the MgO and the activity coefficient of the Mg in Sn increased with increasing temperature. With increasing temperature, the grooves in the SiO4 tetrahedral structure at wavenumbers of 800–1200 cm–1 gradually became shallow and flat, indicating that the complex silicate structure synthesized in the form of SiO2 decreased and the activity of the MgO increased. According to the CaF2-MgO binary phase diagram, the dissolution enthalpy of MgO was calculated to be –16.409 kJ/mol.

Two blue donor-acceptor fluorophores with 1,4,5-triphenylimidazole as the electron-transporting unit and phenothiazine as the hole-transporting unit were synthesized by grafting 1,4,5-triphenylimidazole moieties onto 3- and 3,7-position of the phenothiazine core and characterized by spectroscopic methods. Their thermal stability, photophysical, electrochemical and electroluminescence properties were systematically investigated. These compounds exhibit good thermal stability and show blue emission in dichloromethane solution and thin solid films. The solution-processed doped devices were fabricated by using these fluorophores as the emitting dopant in 1,3-bis(N-carbazolyl)benzene host, in which the device fabricated from the fluorophore containing two 1,4,5-triphenylimidazole moieties exhibited blue emission with a luminance of 648 cd/m2 and external quantum efficiency of 1.48%.

Osteoarthritis (OA) is a well-known chronic degenerative joint disease, with multiple changes in the phenotype of chondrocytes. Circular RNAs (circRNAs) have been shown to be involved in various human diseases, including OA. The purpose of this study was to determine the role of circ_0020093 in OA pathological changes in vitro. C28/I2 cells were treated with interleukin-1 beta (IL-1β) to mimic OA pathological conditions. The expression levels of circ_0020093, miR-181a-5p and ETS-related gene (ERG) mRNA were measured by quantitative real-time PCR (qRT-PCR). For functional analyses, cell proliferative capacity was detected using EdU assay and CCK-8 assay. Inflammatory response was assessed by determining the release of pro-inflammatory factors using ELISA kits. Cell apoptosis was examined by flow cytometry assay. The levels of apoptosis-related proteins and extracellular matrix (ECM)-associated proteins were assessed by Western blot. The binding relationship between miR-181a-5p and circ_0020093 or ERG was confirmed by RNA pull-down assay, dual-luciferase reporter assay or RIP assay. The expression level of circ_0020093 was decreased in IL-1β-treated C28/I2 cells. Circ_0020093 overexpression relieved inflammatory responses, cell apoptosis and ECM degradation in IL-1β-induced C28/I2 cells. Circ_0020093 directly targeted miR-181a-5p, and miR-181a-5p bound to the 3' -untranslated region (3'UTR) of ERG to regulate ERG expression. Circ_0020093 overexpression promoted the expression of ERG by sponging miR-181a-5p. Rescue experiments showed that miR-181a-5p overexpression or ERG knockdown could reverse the inhibitory effects of circ_0020093 overexpression on the pathological changes in IL-1β-induced C28/I2 cells. Circ_0020093 overexpression alleviated IL-1β-induced human chondrocyte inflammatory injury, apoptosis and ECM degradation by targeting miR-181a-5p/ERG pathway.

Hard coatings have important protective effects on the surface of engineering parts due to their high hardness and decent anti-wear properties [...]

A sulphide capacity prediction model of CaO-SiO2-MgO-Al2O3 slags has been developed based on the ion and molecule coexistence theory(IMCT). Sulphide capacity(Cs) of slag for blast furnace (BF) with high Al2O3 in the CaO-SiO2-MgO-Al2O3 system at 1773K were measured by applying slag-metal equilibrium method. The feasibility of the developed IMCT model is verified by the sulphide capacity measured in the experiment. Effects of R(w(CaO)/w(SiO2)), w(MgO)/w(Al2O3) and w(Al2O3) on sulphide capacity were discussed. There is a good linear relationship between the experimental value and the predicted value. Therefore, the theoretical model of ion and molecule coexistence can be used to calculate the sulphide capacity of CaO-SiO2-MgO-Al2O3 quaternary slag system. When w(Al2O3)=20% and w(MgO)/w(Al2O3)=0.5, the sulphide capacity of slag increased with the increase of R. When w(Al2O3)=20% and R=1.30, the sulphide capacity of slag increased with the increase of w(MgO)/w(Al2O3). When R=1.30 and w(MgO)/w(Al2O3)=0.4, the sulphide capacity of slag decreased with the increase of w(Al2O3).

Genome-wide identification and characterization of nuclear factor-Y family in tea plants, and their expression profiles and putative targets provide the basis for further elucidation of their biological functions. The nuclear factor-Y (NF-Y) transcription factors (TFs) are crucial regulators of plant growth and physiology. However, the NF-Y TFs in tea plant (Camellia sinensis) have not yet been elucidated, and its biological functions, especially the putative target genes within the genome range, are still unclear. In this study, we identified 35 CsNF-Y encoding genes in the tea plant genome, including 10 CsNF-YAs, 15 CsNF-YBs and 10 CsNF-YCs. Their conserved domains and motifs, phylogeny, duplication event, gene structure, and promoter were subsequently analyzed. Tissue expression analysis revealed that CsNF-Ys exhibited three distinct expression patterns in eight tea tree tissues, among which CsNF-YAs were moderately expressed. Drought and abscisic acid (ABA) treatment indicated that CsNF-YAs may have a greater impact than other subunit members. Furthermore, through the genome-wide investigation of the presence of the CCAAT box, we found that CsNF-Ys may participate in the development of tea plants by regulating target genes of multiple physiological pathways, including photosynthesis, chlorophyll metabolism, fatty acid biosynthesis, and amino acid metabolism pathways. Our findings will contribute to the functional analysis of NF-Y genes in woody plants and the cultivation of high-quality tea plant cultivars.

It is important to establish the quantitative effect of graphite's 3D morphology on the thermal conductivity of vermicular graphite iron. In the present study, X-ray tomography is utilized to investigate the 3D morphology of graphite in vermicular graphite iron with different vermicularity. A 3D finite element model was built on the basis of graphite's 3D morphology and the equivalent thermal conductivity of vermicular graphite iron can be calculated. The results show that the volume of graphite clusters in vermicular graphite iron is distributed according to y = a (1 − e−bx)c exponential function. The higher the vermicularity, the more obvious the polarization of graphite volume. Compared with vermicularity, 3D connectivity of graphite is a more appropriate characteristic parameter to investigate the thermal conductivity of vermicular graphite iron from the 3D morphology point of view.

Plant-specific WUSCHEL-related homeobox (WOX) transcription factors regulate plant developmental processes, especially those involved in embryogenesis. However, studies on WOX family genes in tea plants do not exist. In this study, a total of eighteen CsWOX members were identified in the tea plant genome and divided into three clades based on the phylogenetic results; they included ancient, intermediate and modern clades, which reflected the evolutionary history of WOX families. Furthermore, ancient clade members had more gene structural variations than other clade members and had unique conserved motifs. The expression profiles of eight tissues showed that six CsWOX genes were highly expressed in at least four tissues, while other genes were expressed at a very low level or not expressed. Moreover, numerous cold-, drought-, ethylene-, methyl jasmonate (MeJA)-, abscisic acid (ABA)-, and gibberellic acid (GA)-responsive cis-elements were observed in the CsWOX promoter regions, and we subsequently investigated their expression patterns under these treatments. Notably, the ancient clade members may play more active roles than members of the other clades in environmental adaptation in tea plants. Our work provides precise information on CsWOX family genes that will benefit the further understanding of their functional roles in tea plants.

Generally, well wear resistance corresponds to low friction coefficient. While, well wear resistance and high friction coefficient are needed in brakes for short braking distance and long serving life. Ceramics possess high hardness which correspond well wear resistance. Cobalt is often used as bond phase of tungsten carbide ceramic, which will increase the toughness of tungsten carbide. While, the stiffness of WC-Co will decrease after cobalt is introduced into tungsten carbide, which will lead to the decrease of friction coefficient. To increase the stiffness and the friction coefficient of WC-Co, nano WC particles were introduced into cobalt binder phase which formed WC-(nano WC-Co). In this work, WC-(nano WC-Co) coatings were prepared through high velocity oxygen fuel (HVOF) spray on the vermicular iron substrate in order to increase friction coefficient and wear resistance simultaneously. The microstructure, mechanical property and wear performance of the coating were investigated. It was found that the microhardness of WC-(nano WC-Co) coatings had the highest hardness of 1393 ± 13 HV with 50% nano WC-10Co-4Cr. Meanwhile, its friction coefficient was obviously increased to 0.7, which was three times higher than that of the vermicular cast iron and higher than both of the micro-sized and nano sized WC-Co. Its wear mass loss of WC-(nano WC-Co) coating was much lower than that of the vermicular cast iron and lower than both of the micro-sized and nano sized WC-Co. The friction coefficient and wear resistance of WC-(nano WC-Co) were increased simultaneously.

Al 7075 alloy, 15 wt.% VN/7075 composites, and 20 wt.% TiB2-TiCx/7075 composites were prepared by ball milling with subsequent hot-pressing sintering. The microstructure, hardness, and wear properties at room temperature to 200 °C of Al 7075-based composites with different reinforcement phases were discussed. The grain uniformity degree values of 15 wt.% VN/7075 composites and 20 wt.% TiB2-TiCx/7075 composites were 0.25 and 0.13, respectively. The reinforcement phase was uniformly distributed in 15 wt.% VN/7075 composites and 20 wt.% TiB2-TiCx/7075 composites, almost no agglomeration occurred. The order of hardness was 20 wt.% TiB2-TiCx/7075 composites (270.2 HV) &gt, 15 wt.% VN/7075 composites (119.5 HV) &gt, Al 7075 (81.8 HV). At the same temperature, the friction coefficient of 15 wt.% VN/7075 composites was the lowest, while the volume wear rate of 20 wt.% TiB2-TiCx/7075 composites was the lowest. With the increase of temperature, the wear mechanism of Al 7075 changed from spalling wear to oxidation wear and adhesion wear. However, the wear mechanisms of 15 wt.% VN/7075 and 20 wt.% TiB2-TiCx/7075 composites changed from abrasive wear at room temperature to wear mechanism (oxidation wear, abrasive wear, and adhesive wear) at medium and low temperature. Comprehensive wear test results indicated that 20 wt.% TiB2-TiCx/7075 composites had excellent tribological properties at medium and low temperature.

In this paper, the mechanism of neutron absorption and common reinforced particles is introduced, and recent research progress on different types of neutron-shielding materials (borated stainless steels, B/Al Alloy, B4C/Al composites, polymer-based composites, and shielding concrete) for transportation and wet or dry storage of spent fuel is elaborated, and critical performance is summarized and compared. In particular, the most widely studied and used borated stainless steel and B4C/Al composite neutron-absorption materials in the field of spent fuel are discussed at length. The problems and solutions in the preparation and application of different types of neutron-shielding materials for spent fuel transportation and storage are discussed, and their research priorities and development trends are proposed.

Plants have evolved regulatory mechanisms at multiple levels to regulate gene expression in order to improve their cold adaptability. However, limited information is available regarding the stress response at the chromatin and translational levels. Here, we characterize the chromatin accessibility, transcriptional, and translational landscapes of tea plants in vivo under chilling stress for the first time. Chilling stress significantly affected both the transcription and translation levels as well as the translation efficiency of tea plants. A total of 3010 genes that underwent rapid and independent translation under chilling stress were observed, and they were significantly enriched in the photosynthesis-antenna protein and phenylpropanoid biosynthesis pathways. A set of genes that were significantly responsive to cold at the transcription and translation levels, including four (+)-neomenthol dehydrogenases (MNDs) and two (E)-nerolidol synthases (NESs) arranged in tandem on the chromosomes, were also found. We detected potential upstream open reading frames (uORFs) on 3082 genes and found that tea plants may inhibit the overall expression of genes by enhancing the translation of uORFs under chilling stress. In addition, we identified distal transposase hypersensitive sites (THSs) and proximal THSs and constructed a transcriptional regulatory network for tea plants under chilling stress. We also identified 13 high-confidence transcription factors (TFs) that may play a crucial role in cold regulation. These results provide valuable information regarding the potential transcriptional regulatory network in plants and help to clarify how plants exhibit flexible responses to chilling stress.

Jasminum sambac is a perennial evergreen shrub plant. With fragrant and aroma, and often used as a raw material for natural spices. In this study, we used white light as the control group, red-light and blue-light as the treatment to study effects of different light on jasmine flowering. Red- light promoted jasmine flowering in advance and increased the number of flower buds, whereas blue-light delayed jasmine flowering and decreased the number of flower buds. There was significant difference on the number of flower buds among the three groups. The top buds' transcriptomes of different light were sequenced by the Illumina Hiseq/Miseq 2000 high-throughput sequencing technology. In total 2 452 457 Unigenes were generated by transcriptome sequencing, of which 1 760 723 Unigenes were annotated into GO, COG, KEGG, KOG, NR, Pfam, Swiss-Prot, NOG databases. There were 894 DEGs in the control group vs red-light group, 2 690 DEGs in the control group vs blue-light group, and 3 828 DEGs in the red-light group vs blue-light group. KEGG Enrichment analysis reveals that the significant enrichment pathways had 6 pathways, including secondary metabolite biosynthesis, phenylpropanoid biosynthesis, indole alkaloid biosynthesis, photosynthesis, plant hormone signaling, and plants-pathogen interactions, and 24 related DEGs were detected by RT-qPCR, the result of which was significantly correlated with the transcriptome data. Through further analysis of transcriptome data, a large number of flowering-related hormones (IAA, ETH, GA, CTK, ABA, SA, JA) signal transduction genes and flowering pathway-related regulatory genes (PHY, CRY1, FPA, AGL and SOC1) and transcription factor (bHLH, MYB, WKRY) family genes were found. The study will help elucidate the differential expression mechanism of different light regulation of jasmine flowering.茉莉花是多年生常绿灌木植物，因其香气芬芳怡人，常被作为天然香料的原材料。本研究通过红光和蓝光分别处理茉莉植株，以白光模拟日光作为对照，观察茉莉植株开花早晚情况，结果表明，红光处理可促使茉莉花提前开花且增加花蕾数量，而蓝光延迟茉莉开花但花蕾数量减少，且各组之间花蕾数量差异显著。采用Illumina Hiseq/Miseq 2000 高通量测序技术对红光组、蓝光组及白光组的顶芽部分进行转录组测序，共得到2 452 457 条单基因簇 (Unigene)，其中1 760 723 个Unigenes 注释到GO、COG、KEGG、KOG、NR、Pfam、Swiss-Prot、NOG数据库。差异表达基因分析显示，对照组vs 红光组共获得894 个DEGs，对照组vs 蓝光组共获得2 690 个DEGs，红光组vs 蓝光组共获得3 828 个DEGs，共有的DEGs 有72 个。KEGG 富集分析显示对照组vs 红光组与对照组vs 蓝光组共有的显著富集通路包括次生代谢物生物合成、苯丙素生物合成、吲哚生物碱生物合成、光合作用、植物激素信号传导和植物-病原体相互作用等，并从中筛选出24 条差异表达基因，采用荧光定量PCR 技术检测其表达水平，进行相关性分析，结果表明与转录组数据显著相关。通过对转录组数据进一步分析，发掘出大量调控开花相关的激素 (IAA、ETH、GA、CTK、ABA、SA、JA) 信号转导基因、开花途径相关调控基因 (PHY、CRY1、FPA、AGL 和SOC1) 以及转录因子 (bHLH、MYB、WKRY) 家族基因，有助于阐明不同光质调控茉莉开花的差异表达机理。.

Tea varieties with specific colours have often been studied by researchers. However, previous studies on the albinism of tea plants have mostly been based on plants with different genetic backgrounds or focused on common components in albino tea leaves, such as amino acids, flavones, and carotenoids. In this study, we conducted widely targeted metabolic and transcriptomic analyses between a wildtype tea genotype (Shuixian, LS) and its albino mutant (Huangjinshuixian, HS). At the molecular level, alteration of gene expression levels in the MEP pathway may have reduced the production of chlorophyll and carotenoids in HS, which could be the main cause of the phenotypic changes in HS. At the metabolite level, a large number of metabolites related to light protection that significantly accumulated in HS, including flavones, anthocyanins, flavonols, flavanones, vitamins and their derivatives, polyphenols, phenolamides. This result, combined with an enzyme activity experiment, suggested that the absence of photosynthetic pigments made the albino tea leaves of HS more vulnerable to UV stress, even under normal light conditions. In addition, except for the common amino acids, we also identified numerous nitrogen-containing compounds, including nucleotides and their derivates, amino acid derivatives, glycerophospholipids, and phenolamides, which implied that significant accumulation of NH4+ in albino tea leaves could not only promote amino acid synthesis but could also activate other specialized metabolic pathways related to nitrogen metabolism. In conclusion, our results provide new information to guide further studies of the extensive metabolic reprogramming events caused by albinism in tea plants.

To understand the surface evolution in unsteady thermal environment of diesel engine, piston Al–Si–Cu alloy was ablated by a high frequent pulsing carburizing oxyacetylene combustion. The tested samples displayed good correlation with the characteristics of some bench tested pistons. As the loading cycles increased, the roughness slightly declined first and then rose sharply. Hardness evolution, micro-morphology, element and phase analysis suggested the surface roughness was mainly controlled by the thermal stress induced defects. And in combination with thermodynamics, the source of Al in surface deposited rimous carbon was ascertained to be chemical reactions between carburizing combustion and the Al–Si–Cu alloy.

Atmospheric plasma-sprayed multi-sized porous structures in thermal barrier coatings (TBCs) were constructed with hollow spherical (HOSP) 8YSZ powders and polypropylene pore formers. The mechanical properties of the multi-sized TBCs were investigated through the nanoindentation method as comparations of the as-sprayed coating and those serving at 1100 °C for a long-term. The results showed that the introduction of the multi-sized pores into TBCs could lead to the decrease of the hardness and modulus as well as the increase of fracture toughness. The hardness and modulus of the coating increased, and the fracture toughness of the coating decreased with the prolongation of the serving times at high temperatures. The mechanical properties of the coating became stable after 60 days’ serving at 1100 °C. The hardness, elastic modulus and fracture toughness of the TBCs increased to 6.51, 7.79, 10.04 GPa and 126.36, 135.13, 145.22 GPa as well as 1.049, 1.157, 1.255 MPa·m0.5, respectively, corresponding to the multi-sized porous TBCs with 0%, 10% and 15% PP powders. The nano-size pores disappeared gradually in the multi-sized TBCs during serving at 1100 °C. The macropores deposited between the ceramic particles penetrated with little diffusion and were not easy to disappear. The introduction of a multi-scale pore structure into the TBCs could improve the stress-strain tolerance of the TBCs.

The multi-arc ion plating technology is used to prepare CrN coating on the valve seat material surface. Results show that the surface grains gradually increase in size and becomes less uniform with the increase of the Cr target current. At different Cr target currents, the main phases of the CrN coating are Cr, CrN, and Cr2N. The critical load of the coating and matrix is 49.2 N. When the Cr target current is 65 A, the nano-hardness is maximum (18.84 GPa), and Young ’s modulus is 255.41 GPa. The CrN coating can reduce the friction coefficient of the valve seat material from 0.62 to 0.48, thereby improving the wear-resistance behavior. The main wear mechanism is abrasive wear.

T6 heat treated piston aluminium alloy (Al-13Si-4Cu-2Ni-1Mg-0.25Mn) were further aged at 350 °C and 420 °C, respectively, for various time (0–1000 h). The microstructures of the re-aged alloy were analyzed using optical microscope (OM, Nicon300) and transmission electron microscope (TEM, JEM-2010). The tensile strengths at room and 350 °C, as well as high cycle bending fatigue of the alloy were tested. The results show that the Al11Cu5Mn3 nanoparticles will precipitate during the elevated re-aging process. The volume fraction formed during re-aging at 420 °C is higher than that formed at 350 °C. Both room temperature (RT) and 350 °C tensile strengths, as well as the high cycle fatigue life of the alloy after being re-aged at 420 °C are higher than those of re-aged at 350 °C due to the notable precipitation strengthening effect of nano particles Al11Cu5Mn3.

Two T6 (500°C × 3 h, water quenching and 210°C × 6 h, air cooling) samples of Al-13Si-5Cu-2Ni-1Mg alloy were furture heated to 350°C and 420°C, respectively for various times. The tensile strength of the alloy, measured at both room temperature and 350°C is observed to abnormally increase, especially for the samples that were heated to 420°C. Al11Cu5Mn3 nanoparticles that form stably during these heating processes exhibit a higher volume fraction after the exposure to 420°C than that obtained by the exposure to 350°C. These nanoparticles were responsible for enhancing the alloy's tensile properties because of the precipitation strengthening effect of the second nano-phase.

The high-temperature oxidation behavior of vermicular iron with different vermicular graphite rates was analyzed at 530 °C for 0–500 h. As the vermicular graphite rate decreased, the oxidation mass gains decreased rapidly. Inside vermicular iron, graphites are interconnected coral-like channels that provide a pathway for oxygen diffusion. The oxide speed reduced with time. Graphites were the main diffusion channel for oxygen. During the oxidation procedure, pearlites were decomposed into ferrite and cementite. The tensile strength, elongation, and hardness were all reduced after oxidation.

In the present work, ribbon and 2-mm rod samples of Mg–Zn–Ca–Mn alloys were prepared by melt-spinning and copper mold injection methods, respectively. Effects of Mn doping on glass-forming ability and corrosion performance in simulated body fluid of Mg65Zn30Ca5 alloy were studied through X-ray diffraction, scanning electron microscopy, differential scanning calorimeter, and electrochemical and immersion tests. Results show that with the Mn addition increasing, all the ribbon samples are completely in amorphous state. However, the microstructure of 2-mm rod samples transfers from fully amorphous for the Mn-free alloy to almost polycrystalline state with precipitated Mg, Mn, and MgZn phases. Glass-forming ability of Mg65Zn30Ca5 alloy is decreased by Mn addition. Results of electrochemical and immersion tests demonstrate that the Mn-doped samples exhibit more negative corrosion potential and larger corrosion current density, suggesting that the corrosion resistance decreases with doping amount of Mn element increasing.

The creep behavior accompanying oxidation of a compacted graphite cast iron (CGI) containing Cu, Mo and Sn elements was studied at temperatures ranging from 350 °C to 550 °C and creep loads ranging from 40 MPa to 150 MPa. The creep damage was observed using both optical and scanning electron microscopy (SEM). The results showed that obvious creep deformation occurred when T / T m ＞0.5 ( T is testing temperature, T m is melting temperature of the CGI) and the load is higher than 150 MPa. The creep deformation in specimen was accounted from three parts: (I) deformation of matrix, (II) initiation and propagation of creep cavities and (III) debonding between graphite and matrix. In addition, two models of crack were observed during creep deformation: (I) cracks propagated preferentially in ferrite phase and combined with debonding between graphite and matrix and (II) creep microcracks caused by creep cavities in the grain boundary. These two types of crack are usually accompanied with oxidation and the former one is more harmful than the latter one because of high crack propagation rate accelerated by interfacial debonding indirectly. Finally, the mechanism of creep deformation and fracture was discussed.

Thermal barrier coatings with multi-sized porous structure at micro and nano scales were prepared with hollow spherical YSZ powders and polypropylene powders through atmospheric plasma spraying. The thermal conductivities of the multi-sized thermal barrier coatings after a long-term serving at high temperature were tested through laser flash heating method. Meanwhile, the physical models of thermal barrier coatings with multi-sized porous structure at micro and nano scales were constructed through Ansys Workbench. The evolutions of thermal conductivity of thermal barrier coatings with multi-sized pores after long-term service at 1100 °C were investigated through computation. It was found that the thermal conductivity of the coating increased with the extension of the serving time. When the serving time reached 60 days, the thermal conductivity of the coating tended to be stable and close to the compacted bulk. The computational results were consistent with the tested ones, which could be helpful to explain the thermal conducting evolution in thermal barrier coatings with multi-sized porous structure at nano and micro scales after long-term serving at high temperature.

In situ formation of Al2O3–ZrO2–Y2O3 composite ceramic coating on ZAlSi12Cu3Ni2 aluminum alloy was successfully prepared by plasma electrolytic oxidation (PEO) technology in a zirconate electrolyti...

In this paper, Al2O3/7075 composites were prepared by mechanical alloying with subsequent hot-pressing sintering, and the effect of Al2O3 nanoparticle on the mechanical and tribological behavior of 7075 was studied. The mechanical property results showed that the hardness and compressive strength of Al2O3/7075 composites first increased and then decreased with Al2O3 amount increasing, and 5 wt.% Al2O3 addition made the material exhibit excellent comprehensive mechanical properties. The tribological properties also indicated that 5 wt.% Al2O3 nanoparticle significantly improved the high-temperature wear resistance of 7075 alloys. Thus, all the mechanical and tribological results confirmed that the addition of Al2O3 nanoparticle was a better strengthening way for 7075 alloys at high temperatures.

M42C stainless steel coatings were deposited on the surface of cast iron through atmospheric plasma spray with different plasma arc powers of 30 kW, 35 kW and 40 kW to obtain higher oxidation resistance than that of cast iron. The high temperature oxidation tests were carried out at 400 °C, 530 °C and 700 °C. It was found that the oxidation mass gains of the M42C coatings were much lower than those of cast irons during initial oxidation. With the increase of oxidation temperature and time, the oxidation mass gains of cast irons increased much more quickly than those of the M42C coatings. At 400 °C and 530 °C, the oxidation mass gains of the M42C coatings were higher than that of the M42C bulk. When the temperature reached 700 °C, the oxidation mass gains of the M42C coatings were just a little higher than that of the M42C bulk. Chromite spinel FeCr 2 O 4 were formed which could hinder the further oxidation in the M42C coating. During the service of the M42C coatings at 700 °C, the oxidation resistance of the M42C coating was increased to the level close to that of the bulk.