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Effect of Cooling Rate on the Formation and Morphology of (W,V)Cx in VC-doped WC–Co Cemented Carbide

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Acta Metallurgica Sinica(English Letters) 2017年第2期30卷 146-155页

作者： Xiao-Ou Yi Xiang Huang Chang-Bin liu Dan-Qing Yi Yong Jiang Bin Wang hui-qun liu Li-Yong Chen School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering Central South University Changsha 410083 China Key Laboratory of Nonferrous Materials Science and Engineering Ministry of Education Central South University Changsha 410083 China

The grain growth retardation mechanism and the effect of cooling rate on VC-doped WC–Co cemented carbides were investigated in this ***–30Co and WC–30Co–VC were prepared by powder metallurgy,liquid-phase sintering at 1400 ℃ and followed by water quenching（[150 ℃/s） or furnace cooling（＊0.083 ℃/s）.Based on the results of electron probe microanalysis（EPMA）,we found that WC concentration in the Co binder was independent of VC doping during liquid-phase sintering,hence barely contributing to the retardation of WC grain *** contrast,the（W,V）Cx phase formed at the WC/Co interfaces played a major role in retarding WC grain growth during liquid-phase *** effect of cooling rate on the morphology of（W,V）Cxwas revealed by high-resolution transmission electron microscopy（HRTEM） and energy-dispersive spectroscopy（EDS）.In the water-quenched WC–30Co–VC,（W,V）Cxprecipitates were found as thin layers at the WC/Co *** contrast,both thin layers of similar thickness and nanoparticles of（W,V）Cx were observed in the furnace-cooled *** observations listed above suggested that thin（W,V）Cxlayers were stable structures effectively suppressing the growth of WC grains and their thickness remained independent of the cooling ***（W,V）Cxnanoparticles,however,may be inhibited through rapid cooling,ensuring the VC-doped WC–Co cemented carbides desired toughness.

关键词： WC-Co VC doping (W,V)Cx Water-quenched Furnace-cooled

Effect ofαphase on fatigue crack growth of Ti-6242 alloy

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Journal of Iron and Steel Research International 2017年第8期24卷 811-822页

作者： Hang-wei Zhou hui-qun liu Dan-qing Yi Yu Xiao Xiao-long Zhao Jian Wang Qi Gao School of Materials Science and Engineering Central South UniversityChangsha 410088HunanChina Key Laboratory of Nonferrous Materials Ministry of EducationCentral South UniversityChangsha 410083HunanChina BAOTI Group Ltd. Baoji 721014ShanxiChina

Fatigue crack growth as a function ofαphase volume fraction in Ti-6Al-2Sn-4Zr-2Mo（Ti-6242）alloy was investigated using fatigue testing,optical microscopy,scanning electron microscopy,and transmission electron ***α＋βannealing treatments with different solid solution temperatures and cooling rates were conducted in order to tailor microstructure with differentαphase features in the Ti-6242 alloy,and fatigue crack growth mechanism was discussed after detailed microstructure *** results showed that fatigue crack growth rate of Ti-6242 alloy decreased with the decrease in volume fraction of the primaryαphase（αp）.Samples with a large-sizedαgrain microstructure treated at high solid solution temperature and slow cooling rate have lower fatigue crack growth *** appearance of secondaryαphase（αs）with the increase of solid solution temperature led to crack ***,a fatigue crack growth transition phenomenon was observed in the Paris regime of Ti-6242 alloy with 29.8% αp（typical bi-modal microstructure）and large-sizedαgrain microstructure,owing to the change of fatigue crack growth mechanism.

关键词： Ti-6242 alloy Microstructure tailoring Fatigue crack growth α phase Fatigue crack growth rate Crack propagation transition

Recrystallization and mechanical properties of cold-rolled FeCrAl alloy during annealing

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Journal of Iron and Steel Research International 2020年第5期27卷 549-565页

作者： Xiao-long Liang hui Wang Qian-fu Pan Ji-yun Zheng hui-qun liu Rui-qian Zhang Yang Xu Yu Xu Dan-qing Yi School of Materials Science and Engineering Central South UniversityChangsha 410083HunanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083HunanChina Nuclear Power Institute of China Chengdu 610213SichuanChina Science and Technology on Reactor Fuel and Materials Laboratory Chengdu 610213SichuanChina

The efect of cold rolling and annealing on the microstructure and properties of an Fe-13Cr-4.5Al-2.2Mo-1.1Nb alloy was *** results showed that the recrystallization rate increased with increasing annealing temperature and rolling *** kinetics was constructed based on Johnson-Mehl-Avrami-Kolmogorov *** apparent activation energies of recrystallization were 161.385,144.770,and 95.362 kJ/mol for the samples with 30%,50%,and 70%cold-rolling reduction,*** the cold-rolling reduction increasing,the textureγfber partly changed to//*** annealing,γfber of the alloy with 30%thickness reduction retained,the subgrains disappeared through merging,and the proportion of coincident site lattice grain boundaries increased and became more continuous.30%cold-rolling reduction alloy annealed at 730°C for 120 min not only possessed relatively high yield strength(YS)of^730 MPa and ultimate tensile strength(UTS)of^880 MPa,but also exhibited elongation of^16%at room *** annealing at 730°C for 120 min,70%cold-rolled alloy has fner and more uniform grain,with higher elongation of^22%,YS of^615 MPa and UTS of^774 *** mechanism of mechanical properties diference was explained according to Schmid factor *** results provided an efective way for tuning strength and ductility of FeCrAl alloy.

关键词： FeCrAl ferrite alloy Cold rolling Recrystallization Texture Mechanical property

Superhydrophobic coating on heat-resistant steel surface fabricated by a facile method

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Journal of Iron and Steel Research International 2018年第9期25卷 975-983页

作者： Bo Jiang Gui-jie Li hui-qun liu Dan-qing Yi Ying Zhang Ren-hao Xue Quan Wen Zhi-yuan liu Liang Ning Xian-ming Wang School of Materials Science and Engineering Central South University Changsha 410083 Hunan China Key Laboratory for Nonferrous Materials Science and Engineering Education Ministry Central South UniversityChangsha 410083 Hunan China China Aviation Power Machinery Research Institute Zhuzhou 412002 Hunan China Marine Chemical Research Institute Co. Ltd.Qingdao 266071 Shandong China

Industrial application of superhydrophobic surfaces is often hindered by complicated process and sophisticated machines. A facile wet etching method （sandblast, HCl and sandblast/HCl） with vapor deposition of PFDS （1H, 1H, 2H, 2H- perfluorodecyltriethoxysilane） was applied to fabricate superhydrophobic surface of heat-resistant steel used for vane. The coating component, surface morphology and surface roughness parameters of sample were observed by attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy. Static water contact angle （WCA） of samples with and without PFDS coating was measured by contact angle goniometer. The results showed that WCA values of polished, sandblast, HCl and sandblast/HCl-etched samples are 98°, 97°, 100° and 101°, respectively, and increase to 112°, 148°, 151 ° and 154v after vapor deposition of PFDS. The sandblast/HCl-etched sample with PFDS coating shows higher superhydrophobicity because of very large surface roughness and lotus protrusionlike structure. The superhydrophobicity of this fabricated surface has no obvious change after 38 cycles of the film adhesion test, indicating excellent durability.

关键词： Superhydrophobic surface Vapor deposition PFDS Static water contact angle Heat-resistant steel

Removal of Nitrogen, Phosphorus, and Organic Pollutants From Water Using Seeding Type Immobilized Microorganisms

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Biomedical and Environmental Sciences 2008年第2期21卷 150-156页

作者： LIN WANG LI-JING HUANG LUO-JIA YUN FEI TANG JING-hui ZHAO YAN-qun liu XIN ZENG QI-FANG LUO Institute of Environmental Medicine School of Public Health Tongji Medical College Huazhong University of Science ＆ Technology MOE Key Laboratory of Environment and Health Wuhan 430030 Hubei China

Objective To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms. Methods Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen, phosphorus, and organic pollutants with the seeding type immobilized microorganisms. Correlations between the quantity of heterotrophic bacteria and the total nitrogen （TN）, total phosphorus （TP）, and total organic carbon （TOC） in the two lakes were studied. The dominant bacteria were detected, inoculated to the sludge and acclimated by increasing nitrogen, phosphorus and decreasing carbon source in an intermittent, time-controlled and fixed-quantity way. The bacteria were then used to prepare the seeding type immobilized microorganisms, selecting diatomite as the adsorbent cartier. The ability and influence factors of removing nitrogen, phosphorus, and organic pollutant from water samples by the seeding type immobilized microorganisms were studied. Results The coefficients of the heterotrophic bacterial quantity correlated with TOC, TP, and TN were 0.9143, 0.8229, 0.7954 in Lake P and 0.9168, 0.7187, 0.6022 in Lake M. Ten strains of dominant heterotrophic bacteria belonging to Pseudomonas, Coccus, Aeromonas, Bacillus, and Enterobateriaceae, separately, were isolated. The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24 h, pH=7.0-8.0, and quantity of the immobilized microorganisms=0.75-1g/50 mL. The removal rates of TOC, TP, and TN under the above conditions were 80.2%, 81.6%, and 86.8%, respectively. Conclusion The amount of heterotrophic bacteria in the two lakes was correlated with TOC, TP, and TN. These bacteria could be acclimatized and prepared for the immobilized microorganisms which could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample.

关键词： Heterotrophic bacteria Acclimation Immobilized microorganisms Nitrogen Phosphorus Mixed organic pollutants

Effect ofαphase morphology on fatigue crack growth behavior of Ti−5Al−5Mo−5V−1Cr−1Fe alloy

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Transactions of Nonferrous Metals Society of China 2020年第9期30卷 2459-2471页

作者： Kui-wai CHEN Su-ping PAN hui-qun liu Yong JIANG School of Materials Science and Engineering Central South UniversityChangsha 410083China Advanced Research Center Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

Taking a Ti−5Al−5Mo−5V−1Cr−1Fe alloy as exemplary case,the fatigue crack growth sensitivity and fracture features with various tailoredαphase morphologies were thoroughly investigated using fatigue crack growth rate(FCGR)test,optical microscopy(OM)and scanning electron microscopy(SEM).The tailored microstructures by heat treatments include the fine and coarse secondaryαphase,as well as the widmanstatten and basket weave *** sample with coarse secondaryαphase exhibits better comprehensive properties of good crack propagation resistance(with long Paris regime ranging from 15 to 60 MPa·m1/2),high yield strength(1113 MPa)and ultimate strength(1150 MPa),and good elongation(11.6%).The good crack propagation resistance can be attributed to crack deflection,long secondary crack,and tortuous crack path induced by coarse secondaryαphase.

关键词： Ti−5Al−5Mo−5V−1Cr−1Fe alloy αphase fatigue crack growth fracture feature

Mechanism of retinoid receptors in inhibiting proliferation and inducing apoptosis of human melanoma cell line A375

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Chinese Medical Journal 2005年第17期118卷 1482-1486页

作者： NIU Xin-wu PENG Zhen-hui FENG Jie MA hui-qun liu Chao YUAN Jing-yi Department of Dermatology Second Hospital of Xi＇an Jiaotong University Xi＇an 71004 China

Malignant melanoma is a common cancer of skin. Its incidence is growing rapidly in recent years, however, there is no effective therapy for this cancer. Retinoids are metabolites or derivatives of vitamin A. They are essential for growth, differentiation, and maintenance of epithelial tissues. Previous studies showed that retinoids could inhibit growth of many kinds of malignant tumor cell lines and induce its apoptosis, including malignant melanoma cell lines. Some retinoids have therapeutic action to malignant melanoma, such as all-trans retinoic acid （ATRA） and 13-cis-RA. Retinoids take effects mainly through two kinds of nuclear receptors, retinoic acid receptor （RAR） and retinoic acid X receptor （RXR）. In this study, we have investigated the effects of diverse retinoids and receptor agonists in inhibiting proliferation and inducing apoptosis of human melanoma cell line A375.

关键词： retinoids receptors apoptosis proliferation

Rapid tooth movement through distraction osteogenesis of the periodontal ligament in dogs

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Chinese Medical Journal 2008年第5期121卷 455-462页

作者： AI Hong XU Qing-feng LU Hong-fei MAI Zhi-hui AN Ai-qun liu Guo-ping Department of Stomatology Affiliated Hospital Guangzhou Sun Yat-sen University Third Guangdong 510630 China

Background Animal models are needed for the study of rapid tooth movement into the extraction socket through distraction osteogenesis of the periodontal ligament. Methods Modified distraction devices were placed on eight dogs between the first and third mandibular premolars on the left sides; similar placement of traditional straight wise appliances on the right sides served as the control. The experimental distractors were activated （0.25 mm/d） twice a day and the control devices were activated （100 g） for two weeks with consolidation periods at weeks two, three, six, and ten. Two dogs were sacrificed at each consolidation time point; rates and patterns of tooth movement, loss of anchorage, and periapical films were evaluated, and the affected premolars and surrounding periodontal tissues were decalcified and examined histologically. General observations, X-ray periapical filming and histology examination were performed. Results Distal movement （（3.66±0.14） mm） measured two weeks after modified distraction exceeded that achieved using the traditional device （（1.15±0.21） mm; P 〈0.05）. Loss of anchorage was minimally averaged （0.34±0.06） mm and （0.32±0.07） mm in the experimental and control sides, respectively. By radiography, apical and lateral surface root resorptions on both sides were minimal. Alveolar bone lesions were never evident. Fibroblasts were enriched in periodontal ligaments and bone spicules formed actively along directions of distraction. Conclusions The canine model is suitable for the study of rapid tooth movement through distraction osteogenesis of the periodontal ligament. The technique accelerates tooth movement, periodontal remodeling, alveolar bone absorption, and may induce fibroblast formation, as compared to the traditional orthodontic method, without adversely affecting root absorption, bone loss, tooth mobility and anchorage loss.

关键词： animal model distraction osteogenesis periodontal ligament rapid tooth movement bone formation

Mechanism of retinoid receptors in inhibiting proliferation and inducing apoptosis of human melanoma cell line A375

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中华医学杂志(英文版) 2005年第17期 76-80页

作者： NIU Xin-wu, PENG Zhen-hui, FENG Jie, MA hui-qun, liu Chao and YUAN Jing-yi Department of Dermatology, Second Hospital of Xi’an Jiaotong University, Xi’an 71004, China