Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

Effect of Extenders and Temperatures on Sperm Viability and Fertilizing Capacity of Harbin White Boar Semen during Long-term Liquid Storage

Zhou, J.B.,Yue, K.Z.,Luo, M.J.,Chang, Z.L.,Liang, H.,Wang, Z.Y.,Tan, J.H. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.11

In this study the effect of extenders and temperatures on sperm viability and fertilizing capacity of boar sperm during long-term storage was investigated. Acrosomal integrity, membrane integrity, motility and hypo-osmotic resistance were evaluated by fluorescence and light microscopy. An in vitro fertilization test was performed to assess the fertilizing capacity of stored spermatozoa. The five diluents tested were ranked according to their ability to maintain sperm functional parameters and Zorlesco (ZO) extender with BSA or with PVA instead of BSA produced the best results. Zorlesco extender substituted with PVA (ZO+PVA) was found to maintain motility both at 15 and 20$^{\circ}C$. within 5 days of storage, but the quality of semen stored at 15$^{\circ}C$ decreased thereafter as compared to semen stored at 20$^{\circ}C$ Semen stored at 5$^{\circ}C$ demonstrated rapid loss of motility already within 24 h. Both fertilization and cleavage of semen stored at 20$^{\circ}C$ in ZO substituted with PVA instead of BSA did not change significantly until day 8 of storage. It is therefore concluded that PVA can be used to substitute for BSA and 20$^{\circ}C$ was more suitable than 15$^{\circ}C$ for boar semen storage, and in vitro fertilizing capacity of spermatozoa was maintained for at least 8 days in ZO+PVA at 20$^{\circ}C$.

Response of an Indented Square Tube Under Impact Loading

Tan, Z. H.,Liu, L. S.,Sun, Y. S.,Cho, C. Springer-Verlag 2015 Strength of Materials Vol.47 No.1

Effects of Intra-duodenal Infusion of Limiting Amino Acids on Plasma Insulin-like Growth Factor I, Growth Hormone, Insulin and Liver Insulin-like Growth Factor I mRNA in Growing Goat Fed a Maize Stover-based Diet

Sun, Z.H.,Tan, Z.L.,Yao, J.H.,Tang, Z.R.,Shan, J.G.,Hu, J.P.,Tang, S.X.,Jiang, Y.M. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.5

The effects of intra-duodenal infusion of methionine (Met), lysine (Lys) and leucine (Leu) on dry matter intake (DMI), the concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH) and insulin in plasma, and liver IGF-I mRNA level were investigated in two experiments for Liuyang Black growing wether goats. In Experiment 1, three goats ($10.0{\pm}0.1$ kg) were fitted with ruminal, proximal duodenal and terminal ileal fistulaes to determine the infusion amounts of Met, Lys and Leu at the duodenum according to essential amino acid flows into the duodenum and their apparent digestibility. The infusion amounts were 0.77 g/d, 0.91 g/d and 0.58 g/d respectively. In Experiment 2, 4 groups of goats (($10.0{\pm}0.2$ kg) for each group, were cannulated at the duodenum, and were infused with a mixture of Met, Lys and Leu (Control), or mixtures with 21% Met, Lys or Leu replaced with glutamate respectively on a nitrogenous basis. The replacement of 21% Met, Lys or Leu with glutamate did not affect intakes of maize stover, concentrate or both (p>0.05) when compared with the control. The replacement of 21% Met or Lys significantly (p<0.05) reduced plasma GH, insulin and IGF-I concentrations and liver IGF-I mRNA level. The replacement of 21% Leu with glutamate reduced (p<0.05) plasma IGF-I concentration only, but not plasma insulin and GH, as well as liver IGF-I mRNA level (p>0.05). The close relationships between supplying Met and Lys in the lumen of the duodenum and plasma IGF-I, GH and insulin concentrations, as well as liver IGF-I mRNA level in this study indicate that the effects of the limiting amino acids on nutrition of animals are likely intermediated via their effects on these hormones, and these hormone profiles could be used as intermediate markers for the limiting order of amino acids.

Use of In vitro Gas Production Technique to Investigate Interactions between Rice Straw, Wheat Straw, Maize Stover and Alfalfa or Clover

Tang, S.X.,Tayo, G.O.,Tan, Z.L.,Sun, Z.H.,Wang, M.,Ren, G.P.,Han, X.F. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.9

Measurement of gas produced during in vitro fermentation was used to investigate the fermentation characteristics and interactions of rice straw, wheat straw or maize stover mixed with alfalfa or clover at proportions of 100:0, 75:25, 50:50, 25:75 and 0:100, respectively. Cumulative gas production was recorded at 2, 4, 8, 12, 16, 24 and 48 h of incubation, and the Gompertz function was used to describe the kinetics of gas production. In vitro dry matter and organic matter disappearances (IVDMD and IVOMD) were determined after 48 h incubation. The rate of gas production of clover was higher (p<0.05) than that of rice straw, wheat straw, maize stover and alfalfa when straws and hays were incubated separately. Increasing the proportion of alfalfa in the straw-alfalfa mixtures increased (p<0.05) the rates, but not the maximum volume of gas production. However, both rate and the maximum volume of gas production were increased (p<0.01) as the proportions of clover increased in the straw-clover mixtures. The cumulative gas production at 48 h, IVDMD and IVOMD showed no consistent interaction effects between different mixtures of cereal straws and hays. The extent of interactive effects was affected by the types of cereal straw, legume hay and their proportions in the mixture. The appropriate combination for the mixture of rice straw or maize stover with leguminous hays was 75:25 and 25:75, respectively. The better combination occurred at a proportion of 50:50 for the mixture of wheat straw and alfalfa. We conclude that the suitable proportion of low-quality straw and high quality legume hay combination should be considered in the ration formulation system of ruminants according to the extent of positive interactive effects.

Effect of ruthenium on high-temperature creep rupture life of a single crystal nickel-based superalloy

Tan, X.P.,Liu, J.L.,Jin, T.,Hu, Z.Q.,Hong, H.U.,Choi, B.G.,Kim, I.S.,Jo, C.Y. Elsevier Sequoia 2011 Materials science & engineering. properties, micro Vol.528 No.29

The addition of 3wt% ruthenium (Ru) has been found to improve the creep rupture lives of a single crystal Ni-based superalloy under both conditions of 1100<SUP>o</SUP>C/150MPa and 1000<SUP>o</SUP>C/310MPa. Creep curve analysis indicates that the creep mechanisms are different from each condition. The improvement of creep rupture lives by 3wt% Ru addition is discussed not only from the view of dislocation movement but also the γ' phase evolution. The change of γ/γ' lattice misfit in the initial microstructure is believed to be the key role of Ru on the high-temperature creep deformation. The larger negative lattice misfit caused by an addition of 3wt% Ru induces smaller and more regular γ' particles in the initial state, as well as denser dislocation networks at the γ/γ' interface during creep. These two aspects are crucial to the high-temperature creep rupture life. In addition, a little topologically close-packed (TCP) phases are observed after creep rupture in the two experimental alloys.

Mutant ubiquitin found in Alzheimer's disease causes neuritic beading of mitochondria in association with neuronal degeneration

Tan, Z,Sun, X,Hou, F-S,Oh, H-W,Hilgenberg, L G W,Hol, E M,van Leeuwen, F W,Smith, M A,O'Dowd, D K,Schreiber, S S Nature Publishing Group 2007 CELL DEATH AND DIFFERENTIATION Vol.14 No.10

A dinucleotide deletion in human ubiquitin (Ub) B messenger RNA leads to formation of polyubiquitin (UbB)+1, which has been implicated in neuronal cell death in Alzheimer's and other neurodegenerative diseases. Previous studies demonstrate that UbB+1 protein causes proteasome dysfunction. However, the molecular mechanism of UbB+1-mediated neuronal degeneration remains unknown. We now report that UbB+1 causes neuritic beading, impairment of mitochondrial movements, mitochondrial stress and neuronal degeneration in primary neurons. Transfection of UbB+1 induced a buildup of mitochondria in neurites and dysregulation of mitochondrial motor proteins, in particular, through detachment of P74, the dynein intermediate chain, from mitochondria and decreased mitochondria–microtubule interactions. Altered distribution of mitochondria was associated with activation of both the mitochondrial stress and p53 cell death pathways. These results support the hypothesis that neuritic clogging of mitochondria by UbB+1 triggers a cascade of events characterized by local activation of mitochondrial stress followed by global cell death. Furthermore, UbB+1 small interfering RNA efficiently blocked expression of UbB+1 protein, attenuated neuritic beading and preserved cellular morphology, suggesting a potential neuroprotective strategy for certain neurodegenerative disorders.Cell Death and Differentiation (2007) 14, 1721–1732; doi:10.1038/sj.cdd.4402180; published online 15 June 2007

Effect of Ru additions on very high temperature creep properties of a single crystal Ni-based superalloy

Tan, X.P.,Liu, J.L.,Jin, T.,Hu, Z.Q.,Hong, H.U.,Choi, B.G.,Kim, I.S.,Jo, C.Y.,Mangelinck, D. Elsevier Sequoia 2013 Materials science & engineering. properties, micro Vol.580 No.-

The creep deformation of three single crystal Ni-based superalloys with various Ru contents has been investigated to clarify the effect of Ru additions at very high temperatures and low stresses conditions. The creep properties were significantly improved by Ru additions under the conditions of 1150<SUP>o</SUP>C/100MPa and 1180<SUP>o</SUP>C/70MPa. It is noted that obvious γ' phase dissolution occurs during the entire creep deformation at very high temperatures. It differs from the typical high-temperature creep curves that a short incubation period occurs before the primary creep stage during the creep deformation at very high temperatures. Ru additions are able to produce denser interfacial dislocation networks and improve the stability and homogeneous configuration of interfacial dislocations; and promote the high-temperature stability of γ' phase and formation of perfect γ' rafting. It is thus shown that Ru additions reduce the minimum creep rate, and prolong the secondary creep stage accordingly. The topological inversion of γ/γ' microstructure did not occur under both conditions. The origin of the rapid increase of creep rate is closely relevant to the unstable propagation of micro-cracks in the vicinity of porosity in necked regions.

Effect of Ruthenium on Precipitation Behavior of the Topologically Close-Packed Phase in a Single-Crystal Ni-Based Superalloy During High-Temperature Exposure

Tan, X.,Liu, J.,Jin, T.,Hu, Z.,Hong, H. U.,Choi, B. G.,Kim, I. S.,Yoo, Y. S.,Jo, C. Y. Springer Science + Business Media 2012 Metallurgical and Materials Transactions A - Physi Vol.43 No.10

Variation of microstructure by Ru additions in a single crystal Ni based superalloy

Tan, X.P.,Liu, J.L.,Jin, T.,Hu, Z.Q.,Hong, H.U.,Choi, B.G.,Kim, I.S.,Jo, C.Y.,Mangelinck, D. Maney Publishing 2014 Materials Science and Technology Vol.30 No.3

The microstructural variation of three single crystal Ni based superalloys with various Ru contents has been investigated. The as cast, solid solution and fully heat treated microstructures were quantitatively analysed. The size of gamma' phase was decreased both in dendrite core and interdendritic regions with Ru additions after a solid solution heat treatment. Appropriate heat treatment schemes of three alloys were determined in terms of quantitative and qualitative microstructural characterisation. It was found that the size and volume fraction of gamma' phase were decreased, and the width of c matrix channels was reduced in the dendrite core regions of fully heat treated microstructure with the additions of Ru. Moreover, the well known reverse partitioning occurred with increasing Ru content. The gamma/gamma' lattice misfits changed from positive to negative and became more negative with Ru additions. The variation of gamma/gamma' lattice misfit was caused by the changes of partitioning ratios of alloying elements via Ru additions.