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Journal of Iron and Steel Research International 2015年第9期22卷 864-869页

作者： Xin-ning ZHANG Ying-dong QU rong-de li School of Materials Science and Engineering Shenyang University of Technology

The impact toughness of EN-GJS-400-18-LT ductile iron was measured by Charpy V-notch impact test at temperature between-80 and 20℃.The fracture properties were tested under instrumented impact *** impact fracture energy,crack initiation and propagation energy,dynamic loads and the ductile to brittle temperature were ***-dimensional reconstruction of impact fracture morphology was accomplished by confocal laser scanning *** results of quantitative fractography indicate that cleavage fracture produces flatter fracture surfaces accompanying with less absorbed energy during the impact fracture *** indicates that fracture roughness has a close relationship with crack propagation energy at low temperature.

关键词： graphite nodule ductile to brittle transition cleavage fracture deformation twin three-dimensional reconstruction

Cementites decomposition of a pearlitic ductile cast iron during graphitization annealing heat treatment

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Journal of Iron and Steel Research International 2017年第8期24卷 838-843页

作者： Min-qiang Gao Ying-dong Qu Guang-long li Jun-hua You rong-de li School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina

Cementites decomposition of a pearlitic ductile cast iron during graphitization annealing heat treatment was *** and microstructures of heat treated samples were observed using a scanning electron microscope and mechanical properties were measured by a universal tensile test *** results indicated that during isothermal annealing at 750°C,the tensile strength of pearlitic ductile cast iron was increased to a peak value at 0.5h,and decreased gradually thereafter but the elongation was enhanced with the increase of annealing ***,the diffusion coefficient of carbon atoms could be approximately calculated as 0.56μm2/s that could be regarded as the shortrange *** the holding time was short（0.5h）,diffusion of carbon atoms was incomplete and mainly occurred around the graphites where the morphology of cementites changed from fragmentized shape to granular *** addition,the ductile cast iron with tensile strength of 740MPa and elongation of 7% could be achieved after graphitization annealing heat treatment for *** principal factors should be taken into ***,the decomposition of a small amount of cementites was beneficial for increasing the ductility up to elongation of 7%.Second,the diffusion of carbon atoms from cementites to graphites could improve the binding force between graphites and matrix,enhancing the tensile strength to 740 MPa.

关键词： Pearlitic ductile cast iron Cementite decomposition Diffusion Carbon atom Graphitization annealing heat treatment

Effect of secondary aging on microstructure and properties of cast Al-Cu-Mg alloy

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China Foundry 2023年第1期20卷 71-77页

作者： Rui-ming Su Yong-xin Jia Jian Xiao Guang-long li Ying-dong Qu rong-de li School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Guizhou Yonghong Aviation Machinery limited liability Company Guiyang 550009China

To obtain better comprehensive properties of cast Al-Cu-Mg alloys,the secondary aging(T6I6)process(including initial aging,interrupted aging and re-aging stages)was optimized by an orthogonal *** microstructures of the optimized Al-Cu-Mg alloy were observed by means of scanning electron microscopy and transmission electron microscopy,and the properties were investigated by hardness measurements,tensile tests,exfoliation corrosion tests,and intergranular corrosion *** show that the S phase andθ’phase simultaneously exist in the T6I6 treated *** increasing the temperature of the interrupted aging in the T6I6 process can improve the mechanical properties and corrosion resistance of Al-Cu-Mg *** optimal comprehensive properties(tensile strength of 443.6 MPa,hardness of 161.6 HV)of the alloy are obtained by initial aging at 180℃for 2 h,interrupted aging at 90℃for 30 min,and re-aging at 170℃for 4 h.

关键词： cast Al-Cu-Mg alloy secondary aging mechanical properties corrosion resistance strengthening phase

Formation and thermal stability of connected hard skeleton structure in ATX525 cast alloys

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China Foundry 2015年第6期12卷 412-417页

作者： Ke-qiang Qiu Hui-han Zhang Yan Re Ying-lei Ren rong-de li School of Materials Science and Engineering Shenyang University of Technology

The formation and the thermal stability of a connected hard skeleton structure(CHSS) in the matrix of Mg-5Al-2Sn-5Ca(ATX525) alloy were investigated by using X-ray diffractometer, scanning electron microscopy, differential scanning calorimeter, creep tester and isothermal treatment method. The results indicated that the CHSS composed of Mg2(Al,Ca) and Al2 Ca intermetallics was formed into a typical eutectic structure and no obvious change occurred when the samples were isothermally treated at 250 °C for 96 h and 350 °C for 72 h, respectively. It became a chained structure when isothermally treated at 450 °C for 48 h. The dissolution and reconstruction processes, however, were observed for the CHSS when the processing temperature was up to 550 °C. The creep life at the stress-temperature condition of 50MPa/200°C for the alloy treated at 450 °C for 48 h was as high as 510 h, and the strain at creep time of 100 h was as low as 0.03%, which indicated that the present alloy has not only a good thermal stability, but also a better heat resistance.

关键词： Mg cast alloy connected hard skeleton structure isothermal treatment thermal stability heat resistance

Refinement and fracture mechanisms of as-cast QT700-6 alloy by alloying method

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China Foundry 2017年第1期14卷 16-21页

作者： Min-qiang Gao Ying-dong Qu rong-de li Ke Jiang Jun-hua You School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

The as-cast QT700-6 alloy was synthesized with addition of a certain amount of copper, nickel, niobium and stannum elements by alloying method in a medium frequency induction furnace, aiming at improving its strength and toughness. Microstructures of the as-cast QT700-6 alloy were observed using a scanning-electron microscope （SEM） and the mechanical properties were investigated using a universal tensile test machine. Results indicate that the ratio of pearlite/ferrite is about 9：1 and the graphite size is less than 40 tJm in diameter in the as-cast QT700-6 alloy. The predominant refinement mechanism is attributed to the formation of niobium carbides, which increases the heterogeneous nucleus and hinders the growth of graphite. Meanwhile, niobium carbides also exist around the grain boundaries, which improve the strength of the ductile iron. The tensile strength and elongation of the as-cast QT700-6 alloy reach over 700 MPa and 6%, respectively, when the addition amount of niobium is 0.8%. The addition of copper and nickel elements contributed to the decrease of eutectoid transformation temperature, resulting in the decrease of pearlite lamellar spacing （about 248 rim）, which is also beneficial to enhancing the tensile strength. The main fracture mechanism is cleavage fracture with the appearance of a small amount of dimples.

关键词： as-cast QT700-6 alloy microstructure graphite refinement pearlite lamellar spacing

Optimal geometrical configuration and oxidation state of cobalt cations in spinel oxides to promote the performance of li-O_(2) battery

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Nano Research 2024年第1期17卷 221-227页

作者： Yu Zhang Shuting Zhang Mengwei Yuan Yufeng li rong liu Caiyun Nan Chen Chen Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China X-ray diffraction Lab Analytical and Testing CenterBeijing Normal UniversityBeijing 100875China

Co_(3)O_(4) is considered as one of promising cathode catalysts for lithium oxygen(li-O_(2))batteries,which contains both tetrahedral Co^(2+)sites(Co^(2+)Td)and octahedral Co^(3+)sites(Co^(3+)Oh).It is important to reveal the effect of optimal geometric configuration and oxidation state of cobalt ion in Co_(3)O_(4) to improve the performance of li-O_(2) ***,through regulating the synthesis process,Co^(2+)and Co^(3+)sites in Co_(3)O_(4) were replaced with Zn and Al atoms to form materials with a unique Co *** li-O_(2) batteries based on ZnCo_(2)O_(4) showed longer cycle life than that of CoAl_(2)O_(4),suggesting that in Co_(3)O_(4),the Co^(3+)Oh site is a relatively better geometric configuration than Co^(2+)Td site for li-O_(2) *** calculations revealed that Co^(3+)Oh sites provide higher catalysis activity,regulating the adsorption energy of the intermediate liO_(2) and accelerating the kinetics of the reaction in batteries,which further leads to the change of the morphology of the discharge product and ultimately improves the electrochemical performance of the batteries.

关键词： lithium oxygen(li-O_(2))batteries geometrical configuration oxidation state lithium peroxide

Effect of TiO_(2)nano-ceramic particles on microstructure and mechanical properties of Al_(0.4)CoCrFe_(2)Ni_(2)high-entropy alloy

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China Foundry 2022年第6期19卷 528-534页

作者： Hao Qi Guang-long li Wei Zhang Qing-yao Lü rong-de li Si-chen Xie Yu Shi Bo Yu Rui-run Chen Ying-dong Qu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China State Key Laboratory of light Alloy Casting Technology for High-end Equipment Shenyang Research Institute of Foundry Co.Ltd.Shenyang 110022China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Al_(0.4)CoCrFe_(2)Ni_(2)high-entropy alloys with different additions of TiO_(2) nanoceramic particles(0,1.25vol.%,2.5vol.%,3.75vol.%and 5vol.%,respectively)were prepared by using the vacuum arc melting *** effects of TiO_(2) addition on the crystal structure,microstructures and mechanical properties of the alloy were investigated by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and tensile *** microstructure analysis shows that the TiO_(2)nano-ceramic particles added in the alloy are decomposed,and a small amount of Al_(2)O_(3)and a great number of intermetallic compounds(γ'phases)with simple cube structure are ***γ'phases are enriched at inter-dendrite,which increases the resistance of dislocation movement during the deformation of the alloy,thus balancing the problem of high plasticity and low strength of the *** the addition of TiO_(2)is 2.5vol.%,the strength of the high-entropy alloy reaches the maximum of 489 MPa,which is 11.1%higher than the matrix alloy composed of single FCC phase.

关键词： high-entropy alloy TiO_(2)nano-ceramic particles microstructure mechanical property

Influence of Cr element on impact fracture process of ductile Ni-resistant alloyed iron at low temperature

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China Foundry 2016年第1期13卷 42-46页

作者： Ke Jiang Ying-dong Qu Jun-hua You rong-de li Qing-chun Xiang Yu-xiong Zhou School of Materials Science and Engineering Shenyang University of Technology

In this study, in order to investigate the influence of Cr element on the impact fracture process of ductile Ni-resistant alloyed iron at low temperature, different contents of Cr element were added to ductile Ni-resistant(DNR) austenitic alloyed iron. The experimental results show that Cr addition can increase the hardness of the DNR alloyed iron, but it has an destructive effect on low-temperature impact properties. Through the analysis of the dynamic load and absorbed energy of samples with different Cr contents in the impact fracture process, and the comparison of the impact fracture process at room and low temperatures, it reveals that Cr addition into the DNR alloyed iron can facilitate the formation of the carbide mixture in Mn23C6 and Cr23C6 with homogeneous and discontinuous distribution. Meanwhile, Cr addition also can improve the the maximum dynamic load and crack initiation energy at low temperature, but has no obvious effect on the yield behavior of the DNR alloyed iron in the impact fracture process. Compared with the impact crack propagation process at room temperature, the metastable propagation energy at low temperature declines significantly with an increase in Cr content. This is because the micro-cracks that caused by the carbides weaken the matrix, resulting in the decline of impact crack propagation resistance. The fracture analysis results also show that the impact fracture mechanism gradually transforms from ductile to brittle with an increase in Cr content at low temperature. It explains that too much Cr addition can lead to brittle fracture even though the austenitic matrix has a good toughness at low temperature.

关键词： Ni-resistant alloyed iron carbide impact fracture low temperature Cr addition

Evidence of refilled chamber gas pressure enhancing cooling rate during melt spinning of a Zr_(50)Cu_(40)Al_(10) alloy

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China Foundry 2015年第4期12卷 299-304页

作者： Hong-wang Yang Peng Zhang M.J.Tan Yuan Ge Wan-ping Tian Rui-chun Wang rong-de li School of Materials Science and Engineering Shenyang University of Technology School of Mechanical and Aerospace Engineering Nanyang Technological University

The influence of the refilled gas pressure on the glass forming behaviour of one of the best ternary glass forming alloys Zr50Cu40Al10 was studied for the melt spinning process. The amorphicity of as-quenched ribbons was characterized by X-ray diffraction （XRD） and differential scanning calorimetry （DSC）. The refilled chamber atmospheric pressure is crucial to the cooling rate of melt spinning. At high vacuum, at pressure less than 0.0001 atm, fully crystalline fragments are obtained. Monolithic amorphous ribbons were only obtained at a gas pressure of 0.1 atm or higher. The extended contact length between thecribbons and the copper wheel contributes to the high cooling rate of melt spinning. Higher chamber gas pressure leads to more turbulence of liquid metal beneath the nozzle; therefore, lower pressure is preferable at practical melt spinning processes once glass forming conditions are fulfilled.

关键词： metallic glass amorphous alloy melt spinning glass forming behaviour

Vibration Control of A Flexible Marine Riser System Subject to Input dead Zone and Extraneous Disturbances

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China Ocean Engineering 2024年第2期38卷 271-284页

作者： ZHOU li WANG Guo-rong WAN Min School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China Energy Equipment Institute Southwest Petroleum UniversityChengdu 610500China National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China

An observer-based adaptive backstepping boundary control is proposed for vibration control of flexible offshore riser systems with unknown nonlinear input dead zone and uncertain environmental *** control algorithm can update the control law online through real-time data to make the controller adapt to the environment and improve the control ***,based on the adaptive backstepping framework,virtual control laws and Lyapunov functions are designed for each *** direction interference observers are designed to track the timevarying boundary *** this basis,the inverse of the dead zone and linear state transformation are used to compensate for the original system and eliminate the adverse effects of the dead *** addition,the stability of the closed-loop system is proven by Lyapunov stability *** the system states are bounded,and the vibration offset of the riser converges to a small area of the initial ***,four examples of flexible marine risers are simulated in MATLAB to verify the effectiveness of the proposed controller.

关键词： adaptive backstepping control disturbance observer flexible marine riser input dead zone vibration control