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.

재래 흑돼지와 중국 재래돈간의 Melanocortin Receptor 1(MC1R) 유전자의 유전자형 분석

이성수,양보석,정진관,고서봉,오성종,양영훈,김규일,이찬동,풍서당 한국동물자원과학회 2001 한국축산학회지 Vol.43 No.1

PCR-RFLP analysis of Melanocortin receptor 1 (MC1R) gene was carried out to investigate the genotype distribution in Korean-Native and Chinese-Native pig breeds(Neijiang, Putian, Wannanhua and Jinhua). Allelic variants of MC1R in pigs were analyzed by digestion of BspH I , AccII and Hha I . Ncijiang. Wannanhua and Jinhua had only MC1R*2 allele which is considered to be typical genotype for Meishan and Large Black. Among 20 Korean-Native Pigs and 5 Putian pigs, 10 and 2 heads had the MC1R*3 allele (*2/3 or 3/3), respectively, which was detected in European pig breeds such as Hampshire, Large White, and Pietrain. The remaining animals possessed the genotype MC1R*2/2, probably reflecting the genetic introgression of MC1R*3 allele into Korean-Native and Putian pig breeds by the crossbreeding for improvement. The alleles MC1R*l and MC1R*4, which are considered to be typical allele for European Wild Boar with wild-type coat color and Duroc with red coat color, respectively, were not detected in pig breeds used in this experiment. These results indicate that the analysis of genotype frequencies of MC1R gene may be a useful tool for the conservation of Korean-Native and Chinese-Native pig breeds.

Al_(2)O_(3)-MgO계 캐스터블 내화물의 내침식성 향상

전명곤,연상흠,양정훈,김재준,황규홍,정두화 慶尙大學校 經營行政大學院 2004 工學硏究院論文集 Vol.20 No.-

To improve the mechanical and chemical properties of unfired Al_(2)O_(3) castables which is widely used in metal line of steel-making ladle, the ρ-Al_(2)O_(3) and /or fine MgO was added as a matrix powders and the degree of spinel formation was studied. Because the spinel was formed at the contact areas between Al_(2)O_(3) and MgO particles and the volume of in-situ formed spinel increased more abnormally at the site of Al_(2)O_(3) particles than MgO side, Al_(2)O_(3) aggregates was more recommendable than MgO aggregates. And to compare the degree of spinel formation in the Al_(2)O_(3)-MgO castable refractories, ultrafine SiO_(2) and Al_(2)O_(3) powders were added and their effects on physical properties such as permanent volume expansion and cold crushing strength were examined. For ρ-Al_(2)O_(3) binder, it could be replaced the alumina cement so that the CaO content could be reduced, but low compressive strength and firing shrinkage inhibit it's application to castables. But MgO powders should be added and the finer the MgO powder, the better the residual expansion and in-situ Spinel formation was observed. And due to Spinel formation and dense microstructure, CA_(6) phase would not formed around alumina aggregates during corrosion so that the corrosion resistance was much more increased.

Gli1, a potential regulator of esophageal cancer stem cell, is identified as an independent adverse prognostic factor in esophageal squamous cell carcinoma

Yang, Z.,Cui, Y.,Ni, W.,Kim, S.,Xuan, Y. Springer Science + Business Media 2017 JOURNAL OF CANCER RESEARCH AND CLINICAL ONCOLOGY Vol.143 No.2

<P>Targeting Gli1, a potential diagnostic marker of ESCC stem cells, will have a profound therapeutic and prognostic value.</P>

Effect of welding residual stress redistribution on the Charpy absorbed energy

Yang, Z.,Ha, S.,Jang, B. S.,Lee, Y. 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

<P>Small specimens enclosing the welded joint are cut out when inspection for the welded joint is carried out. The cutting, however, always leads to the redistribution of residual stresses developed in the original welded joint. This study investigated the difference between the primary and secondary absorbed energy of the welded joint. The primary absorbed energy is the absorbed energy when as-weld residual stress (RS) is present. The secondary absorbed energy indicates the absorbed energy when as-weld RS in the welded joint was redistributed by the wire-cutting (WC) process. Finite element (FE) simulation of the plate welding, WC, and Charpy V-notch (CVN) test was performed to examine the effect of residual stress redistribution on the absorbed energy. Results showed that the secondary absorbed energy was, on an average, 7.8 % lower than the primary absorbed energy. This difference indicates that the primary absorbed energy of the welded joint has been underestimated from the perspective of an inspector. The difference in primary and secondary absorbed energy may not be negligible when designing large welded structures such as large pipelines.</P>

Simulation and Technology of Variable cross-section Tube Welding using the Finite Element Method

Z. R. Yang(양조예),Y. S. Lee(이영석) 한국소성가공학회 2014 한국소성가공학회 학술대회 논문집 Vol.2014 No.10

The effect of spin reorientation transition of antiferromagnetic NiO on the Py magnetic anisotropy in Py/NiO/CoO/MgO(0 0 1)

Yang, M.,Li, Q.,N'Diaye, A.T.,Dong, Q.Y.,Gao, N.,Arenholz, E.,Hwang, C.,Wu, Y.Z.,Qiu, Z.Q. Elsevier 2018 Journal of magnetism and magnetic materials Vol.460 No.-

<P><B>Abstract</B></P> <P>Using X-ray Magnetic Linear Dichroism (XMLD) measurement, we investigate the antiferromagnetic (AFM) NiO spin reorientation transition (SRT) in epitaxial NiO/CoO/MgO(0 0 1) system at room temperature and constructed a complete NiO spin phase diagram. Then utilizing Magneto-Optic Kerr Effect (MOKE) combined with a rotation magnetic field (ROTMOKE), we investigated the effect of NiO SRT on the magnetic anisotropy of a ferromagnetic (FM) Py overlayer in Py/NiO/CoO/MgO(0 0 1) system. We find that the Py coercivity and anisotropy only slightly enhanced for Py on top of out-of-plane NiO spins but greatly enhanced for Py on top of in-plane NiO spins. Both the uniaxial and fourfold anisotropies of the Py showed a clear dependence on the NiO spin orientation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spin reorientation transition (SRT) of antiferromagnetic NiO. </LI> <LI> Direct measurement of antiferromagnetic spins using XMLD. </LI> <LI> Quantitative determination of Py magnetic anisotropy using ROTMOKE. </LI> <LI> Demonstration of the effect of the NiO SRT on the Py magnetic anisotropy. </LI> </UL> </P>

Finite Element Analysis on Spread for In-plane Roll-bending Process

Z. J. Li,H. Yang 한국소성가공학회 2010 기타자료 Vol.2010 No.6

The in-plane roll-bending process is a special wedge rolling with a configuration of two conical rolls which can form strips into open ring products. The spread of a ring is usually not considered in previous radius predicting models by Yang et al. [1] and Xian et al. [5]. However, the spread increases to 10% for a ring with average reduction of 56%, and there is a discrepancy between the predicted radius and the experiment. Spread analysis/calculation has become an urgent problem in radius prediction and precision control of unequal deformation in this process. A finite element (FE) model considering spread effect is established and evaluated by experiments. A comparison between the predicted results with/without considering spread by FE analysis and experiments is carried out. The result shows that the predicted results considering spread are much closer to the experiments than those without considering spread effect. Based on the FE simulation, the spread characteristics of the ring with two types of cross section (including partly and entirely compressed cross section) are investigated. It is found that, there exist three spread regions, including outer positive region, middle negative region and inner positive region for the partly compressed ring; and there are outer positive region and inner negative region for the entirely compressed ring. The spread mostly happens at the outer positive region for both types of ring. The effects of process parameters, such as wedge angle, bite location, friction coefficient and rotational speed of roll, on spread for three aluminum alloys, 3A21O, 5A02O and 2A12T4, are investigated. The results indicate that the spread decreases with an increase in wedge angle, whereas increases with the growth of bite location; the spread remains stable with increasing friction coefficient and fluctuates within 3%-8% with a rise in rotational speed of roll. The spread of the partly compressed ring is less than 6%; large spread (larger than 6%) occurs when the ring is entirely compressed; the spread may reach a maximum value of 18.8% for material 5A02O.

Responsiveness to reduced dosage of rituximab in Chinese patients with neuromyelitis optica

Yang, C.-S.,Yang, L.,Li, T.,Zhang, D.-Q.,Jin, W.-N.,Li, M.-S.,Su, N.,Zhangning, N.,Liu, Q.,Shao, Z.-H.,Yu, C.,Shi, F.-D. Ovid Technologies (Wolters Kluwer) - American Acad 2013 Neurology Vol.81 No.8

432-μm Laser’s Beam-waist Measurement for the Polarimeter/Interferometer on the EAST Tokamak

Z. X. Wang,H. Q. Liu,Y. X. Jie,M. Q. Wu,T. Lan,X. Zhu,Z. Y. Zou,Y. Yang,X. C. Wei,L. Zeng,G. S. Li,X. Gao 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.8

A far-infrared (FIR) polarimeter/interferometer (PI) system is under development for measurementsof the current-density and the electron-density profiles in the EAST tokamak. The systemwill utilize three identical 432-μm CHCOOH lasers pumped by a CO2 laser. Measurements of thelaser beam’s waist size and position are basic works. This paper will introduce three methods witha beam profiler and several focusing optical elements. The beam profiler can be used to show thespatial energy distribution of the laser beam. The active area of the profiler is 12.4 × 12.4 mm2. Some focusing optical elements are needed to focus the beam in order for the beam profiler toreceive the entire laser beam. Two principles and three methods are used in the measurement. Thefirst and the third methods are based on the same principle, and the second method adopts an otherprinciple. Due to the fast and convenient measurement, although the first method is a special formof the third and it can only give the size of beam waist, it is essential to the development of theexperiment and it can provide guidance for the choices of the sizes of the optical elements in the nextstep. A concave mirror, a high-density polyethylene (HDPE) lens and a polymethylpentene (TPX)lens are each used in the measurement process. The results of these methods are close enough forthe design of PI system’s optical path.