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Effect of the addition of Mg, Ti, Ni on the decoloration performance of AlCrFeMn high entropy alloy
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作者 Shikai Wu Ye Pan +3 位作者 Jie Lu Ning Wang Weiji Dai Tao Lu 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第8期1629-1635,共7页
Due to the excellent mechanical properties of high entropy alloys(HEAs), they have attracted wide attention of materials researchers, but their functional properties have rarely been reported. In order to study the fu... Due to the excellent mechanical properties of high entropy alloys(HEAs), they have attracted wide attention of materials researchers, but their functional properties have rarely been reported. In order to study the functional properties of HEAs, the decoloration of azo dye Direct Blue 6(DB6) using equiatomic AlCrFeMn and AlCrFeMn M(M=Mg, Ti, Ni) HEAs synthesized by mechanical alloying was reported in this work. The decoloration rate of DB6 by ball-milled(BM) AlCrFeMn was about 3 times faster than that of by BM MgZn-based amorphous alloy, which was the best one reported in the metallic glasses so far. In order to further improve the decoloration efficiency, we considered adding the fifth elements(Mg or Ti or Ni) to AlCrFeMn. Both of Mg and Ti could improve the decoloration performance of AlCrFeMn, but Ni played a negative role. The reaction activity of AlCrFeMnMg and AlCrFeMnTi was more than 2 and 1.2 times faster than that of AlCrFeMn. The effects of initial pH, temperatures and dye concentration on the decoloration efficiency of AlCrFeMnMg during reactions were systematically investigated. The reaction activity of AlCrFeMnMg in alkaline and acidic azo dye solution was about 37.5 and 16.6 times faster than that of neutral solution, respectively. This work had implications in reaching an attractive, low cost and efficient method for functional applications of HEAs. 展开更多
关键词 Alloy design ENVIRONMENT properties Low COST Materials synthesis MECHANICAL MILLING MECHANICAL properities
Main α relaxation and slow β relaxation processes in a La30Ce30Al15Co25 metallic glass
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作者 J.C. Qiao Y.H. Chen +2 位作者 R. Casalini J.M. Pelletier Y. Yao 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第6期982-986,共5页
Dynamic relaxation processes are fundamental to understand the mechanical and physical properties of metallic glasses. In the current work, mechanical relaxations in a La30Ce30Al15Co25 bulk metallic glass were probed ... Dynamic relaxation processes are fundamental to understand the mechanical and physical properties of metallic glasses. In the current work, mechanical relaxations in a La30Ce30Al15Co25 bulk metallic glass were probed by dynamic mechanical analysis. In contrast to many metallic glasses, La30Ce30Al15Co25 metallic glass shows a pronounced slow β relaxation peak. Physical aging below the glass transition temperature Tgleads to an increase of the apparent activation energy and a decrease of the slow β relaxation magnitude. The correlation between the slow β relaxation and the main α relaxation is discussed. 展开更多
关键词 MECHANICAL RELAXATION Dynamic MECHANICAL RELAXATION α RELAXATION β RELAXATION Physical AGING
Physical properties of B4N4-Ⅰ and B4N4-Ⅱ:First-principles study
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作者 马振洋 王鹏 +2 位作者 阎芳 史春蕾 田毅 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第3期283-290,共8页
The structural, mechanical, electronic, mechanical anisotropy, and thermal properties of boron nitride(BN) polymorphs, such as B4 N-4-Ⅰ and B4 N4-Ⅱ, are investigated under ambient pressure utilizing first-principles... The structural, mechanical, electronic, mechanical anisotropy, and thermal properties of boron nitride(BN) polymorphs, such as B4 N-4-Ⅰ and B4 N4-Ⅱ, are investigated under ambient pressure utilizing first-principles generalized gradient approximation calculations using an ultrasoft pseudopotential scheme. The phonon spectra and elastic constants reveal that B4 N4-Ⅰ is dynamically and mechanically stable at the pressure of 0 GPa and temperature of 0 K. Anisotropic calculations indicate that both B4 N4-Ⅰ and B4 N4-Ⅱ exhibit higher anisotropy of Young’s modulus than cubic BN(c-BN). B4 N4-Ⅱ and B4 N4-Ⅰ present indirect and wide band gaps of 5.32 eV and 4.86 eV, respectively. In addition, B4 N4-Ⅰ is more brittle than B4 N4-Ⅱ. Moreover, the minimum thermal conductivity,κmin, of B4 N4-Ⅱ at 300 K is 1.92 W/(cm·K), which is slightly higher than those of B4 N4-Ⅰ and c-BN(1.84 W/(cm-K) and 1.83 W/(cm-K), respectively. However, κmin of B4 N4-Ⅰ is slightly higher than that of c-BN. 展开更多
关键词 BN POLYMORPHS MECHANICAL PROPERTIES electronic PROPERTIES MECHANICAL ANISOTROPIC PROPERTIES
Mechanical Properties of Cells Estimated by Different Models of Micropipette Aspiration
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作者 Weiyi Chen 《医用生物力学》 CAS CSCD 北大核心 2019年第A01期1-2,共2页
Background The mechanical properties are related with many biological functions of cells. Accurate quantification of the mechanical properties of living cells require the combined use of experimental techniques and th... Background The mechanical properties are related with many biological functions of cells. Accurate quantification of the mechanical properties of living cells require the combined use of experimental techniques and theoretical models. Micropipette aspiration (MPA) is one of common techniques in determining mechanical properties of the living cells. The halfspace model (HSM) is employed in MPA technique. However,in the conditions of linear constitutive relations and small deformations,the HSM is inadequate for characterizing the MPA of a spherical cell in two respects. Firstly,the cell size is fairly finite other than semi-infinite to the inner radius of a micropipette;Secondly,cells are compressible,with a Poisson’s ratioνvarying from 0. 2 to 0. 4 (23-25) instead of incompressible (ν=0. 5). Thus,a more accurate model is necessary.In this study,the viscoelastic expressions were derived from our previous MPA test. Then,a sphere model (SM) employed to analyze mechanical properties of rabbit chondrocytes combined with the experimental data. Differences in mechanical properties estimated by different mechanical models were evaluated.Methods A sphere model (SM) was employed. The relative dimension of cell to micropipette and the compressibility of the cell were taken into account,as shown in Fig. 1a.■Fig.1 Sphere model of the MPA of a single cell employing different constitutive relationships The approximate expression for the aspirated length was obtained from our previous study as follows:■Furthermore,assuming that the cell behaves as a homogeneous and isotropic standard linear solid (Fig. 1b),two viscoelastic creep expressions of the aspirated length for incompressible sphere model (ICSM) and for compressible sphere model (CSM) were derived by elastic-viscoelastic correspondence principle and integral transformation as Eqs.(2) and (3)respectively.■Results(1) Comparisons of models The elastic modulus from the ICSM was 47. 4%higher than that of the half-space model (HSM)(P<0. 001). For the CSM,the percentage 展开更多
关键词 micropipette ASPIRATION MECHANICAL MODELS MECHANICAL properties COMPRESSIBILITY of CELL CELL DIMENSION
Wear behavior of light-weight and high strength Fe-Mn-Ni-Al matrix self-lubricating steels
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作者 Liuliu Han Kun Li +3 位作者 Cheng Qian Jingwen Qiu Chengshang Zhou Yong Liu 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第4期623-630,共8页
The good combination of mechanical and tribological properties for self-lubricating materials is crucial. In this work, novel self-lubricating Fe-16.4 Mn-4.8 Ni-9.9 Al-xC(wt%) steels containing graphite phase were fab... The good combination of mechanical and tribological properties for self-lubricating materials is crucial. In this work, novel self-lubricating Fe-16.4 Mn-4.8 Ni-9.9 Al-xC(wt%) steels containing graphite phase were fabricated using mechanical alloying and spark plasma sintering. The compositions of the steels were designed by using thermodynamic calculation, and the effect of carbon addition on the microstructure was further investigated. The steel possesses high hardness of 621 HV, high yield strength of 1437 MPa and good fracture toughness at room temperature. The yield strengths are still above 600 MPa at 600?C.The tribological behavior and mechanical properties from room temperature to 800?C were studied, and the wear mechanisms at elevated temperatures were discussed. The steel has a stable friction coefficient of 0.4 and wear rate in a magnitude of 10-6 mm3/N·m below 600?C. The good tribological properties of the steels were mainly attributed to the high hardness, lubrication of graphite and stable surface oxide layer. 展开更多
关键词 Metal MATRIX composites MECHANICAL alloying MECHANICAL PROPERTIES Tribological PROPERTIES Alloy design
Synthesis of Vanadium Carbide Nanopowders via Mechanical Alloying and Microwave Heating Methods
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作者 YANG Baozhen ZHENG Hongjuan +2 位作者 ZHAO Zhiwei ZHENG Juan CHEN Feixiao 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第2期332-336,共5页
A simple and fast method of preparation of vanadium carbide(V8 C7) nanopowders using mechanical alloying assisted microwave heating method was demonstrated. The micron-sized V2O5 and nano-sized carbon black were used ... A simple and fast method of preparation of vanadium carbide(V8 C7) nanopowders using mechanical alloying assisted microwave heating method was demonstrated. The micron-sized V2O5 and nano-sized carbon black were used as starting materials. The as-prepared powders were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), thermogravimetric and differential scanning calorimetry(TG-DSC), transmission electron microscopy(TEM), and X-ray photoelectron spectroscopy(XPS) techniques. The experimental results show that the V8C7 powders can be obtained by microwave heating at 1 100 ℃ for 1 h(34 wt% C). The synthesized powders show good dispersion and are mainly composed of spherical or near-spherical particles with a mean diameter of about 30 nm. The XPS spectra show that the surface of the specimen mainly consists of V, C, and O three species elements. 展开更多
关键词 VANADIUM CARBIDE mechanical ALLOYING MICROWAVE heating microstructure NANOPOWDERS
Effect of Hygrothermal Cycle Aging on the Mechanical Behavior of Single-lap Adhesive Bonded Joints
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作者 FAN Yisa NA Jingxin +2 位作者 MU Wenlong QIN Guofeng TAN Wei 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第2期337-344,共8页
The aging behavior of single lap joints(SLJ) in hygrothermal cycles was investigated and compared by using a shearing strength test, Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TG/DTG), e... The aging behavior of single lap joints(SLJ) in hygrothermal cycles was investigated and compared by using a shearing strength test, Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TG/DTG), energy dispersive spectrometry(EDS) and scanning electronic microscopy(SEM). The temperature/relative humidity was set at 80 ℃/95% and –40 ℃/30% for 20 cycles, 40 cycles, and 60 cycles(one cycle was 12 hours), respectively. The experimental results show that hygrothermal aging significantly decreases the failure strength of adhesive joints. However, the failure displacement increases as the number of aging cycles increases. In addition, hygrothermal aging changes the failure mode of the adhesive joints from a cohesive fracture in un-aged adhesive layers to an interfacial failure of aged adhesive joints. 展开更多
关键词 SINGLE LAP JOINTS hygrothermal AGING mechanical behavior FTIR TG/DTG EDS
High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite
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作者 Chen Wang Bei-Bei Wang +5 位作者 Dong Wang Peng Xue Quan-Zhao Wang Bo-Lv Xiao Li-Qing Chen Zong-Yi Ma 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第6期677-683,共7页
A 17 vol%SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed)at a very high welding speed of 2000 mm/min for the first time.Microstructural observation indicated th... A 17 vol%SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed)at a very high welding speed of 2000 mm/min for the first time.Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed,due to the significantly reduced peak temperature and duration at high temperature.Therefore,prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed,which was similar to that of the nugget zone.Furthermore,the ultimate tensile strength of the joint was as high as 369 MPa,which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa).This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency. 展开更多
关键词 FRICTION STIR WELDING Metal matrix COMPOSITE High WELDING speed Microstructure Mechanical property
A comprehensive review of cavitation in valves:mechanical heart valves and control valves 预览
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作者 Jin-yuan Qian Zhi-xin Gao +1 位作者 Cong-wei Hou Zhi-jiang Jin 《生物设计与制造(英文)》 CSCD 2019年第2期119-136,共18页
Valves are widely used in various working conditions for their flow control functions,and the cavitation inside valves has been investigated owing to its harm to the valve itself and the connecting downstream parts.Th... Valves are widely used in various working conditions for their flow control functions,and the cavitation inside valves has been investigated owing to its harm to the valve itself and the connecting downstream parts.This paper presents a comprehensive review of the progress that has been achieved in the past years about cavitation in valves including both mechanical heart valves and control valves.The review is divided in the following parts,namely the location where there is a high possibility of the occurrence of cavitation,the parameters that affect cavitation intensity,and the methods to minimize cavitation intensity.It should be noticed that although simulation has been widely used,advanced experiments are still needed in order to obtain accurate analysis of cavitation in valves and the cavitation model still needs to be improved. 展开更多
关键词 CAVITATION MECHANICAL HEART VALVES CONTROL VALVES
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Microstructural Evolution,Mechanical Properties and Thermal Stability of Gradient Structured Pure Nickel
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作者 Xiao Li Bo Guan +4 位作者 Yun-Fei Jia Yun-Chang Xin Cheng-Cheng Zhang Xian-Cheng Zhang Shan-Tung Tu 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第8期951-960,共10页
The microstructural evolution of pure nickel treated by deep rolling(DR)technique with different indent depths was investigated by means of optical microscopy and transmission electron microscopy.The surface roughness... The microstructural evolution of pure nickel treated by deep rolling(DR)technique with different indent depths was investigated by means of optical microscopy and transmission electron microscopy.The surface roughness,hardness and residual stress distribution along the depth from surface were measured.Moreover,the DR-treated sample was annealed at temperatures from 300 to 700℃for 2 h.The results reveal that dislocation movements are the fundamental mechanisms of gradient grain refinement during the DR process.With increasing indent depth of the DR,the gradient microhardness on the cross section of sample significantly increases,the maximum compressive residual stress decreases,and the affecting region of residual stress increases.The results of thermal stability depict that the microstructure can be stable as temperature up to 300℃,and the abnormal grain growth and annealing twins are observed at 600℃. 展开更多
关键词 Deep ROLLING PURE nickel-Microstructural evolution Mechanical properties Thermal stability
Microstructure and mechanical properties of AZ31 magnesium alloy reinforced by I-phase
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作者 Hai-Rong Wu Wen-Bo Du +2 位作者 Shu-Bo Li Ke Liu Zhao-Hui Wang 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第8期733-738,共6页
The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room temper... The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room temperature.The microstructure and tensile properties of composites were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and tensile testing machine at room temperature.The results suggest that the RPW process can effectively refine the matrix and make the I-phase particles distribute uniformly.The ultimate tensile strength and the yield strength of the composites reach their maximum values of 362.3 and 330.5 MPa,respectively,when the amount of I-phase particles added is10 %.Meanwhile,the elongation of the composites decreases sharply. 展开更多
关键词 I-phase REINFORCED COMPOSITE Repeated PLASTIC working Mechanical PROPERTY
Analysis on Mechanical Grain Harvesting Characteristics of Different New Maize Varieties 预览
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作者 Yanlong HAN 《亚洲农业研究:英文版》 2019年第7期80-83,共4页
In order to screen new varieties of suitable mechanical grain harvesting maize, the main agronomic traits, stem traits and harvesting traits of maize in the harvest period were studied through taking 18 main varieties... In order to screen new varieties of suitable mechanical grain harvesting maize, the main agronomic traits, stem traits and harvesting traits of maize in the harvest period were studied through taking 18 main varieties and newly-tested varieties in Liaoning Province as materials. It obtained the following results. Between different maize varieties, there was significant difference in the mechanical grain yield, and the quality difference was also significant. Ten test varieties including Tieyan 818 and Danyu 311 obtained higher yield than the control variety. The moisture content at harvesting was 26.0%-30.4%, the average moisture content was 28.22%, the average breaking rate was 6.52%, the average impurity rate was 1.91%, and the average yield loss rate was 6.33%. Danyu 212, Tieyan 58, Dika 516 and Danyu 801 had higher yield, and the grain moisture content, broken rate, impurity rate and yield loss rate were relatively low, so these varieties are suitable for promoting mechanical harvesting. Among the 8 traits surveyed, the traits positively correlated with yield were the percentage of broken stalks, degree of lodging, moisture content at harvesting, and percentage of kernel weight in ear weight, and traits negatively correlated with the yield included plant height, ear height, percentage of bare plants, and degree of lodging. Therefore, high moisture content is the main problem in the mechanical grain harvesting of maize, it is required to properly select early maturing varieties. 展开更多
关键词 MAIZE MECHANICAL GRAIN HARVESTING Broken RATE IMPURITY RATE
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Mechanical Relaxation of a Ti36.2Zr30.3Cu8.3Fe4Be21.2 Bulk Metallic Glass:Experiments and Theoretical Analysis
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作者 J.C.Qiao Y.H.Chen +3 位作者 G.J.Lyu K.K.Song J.M.Pelletier Y.Yao 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第6期726-732,共7页
The dynamic mechanical relaxation behavior of Ti36.2Zr30.3Cu8.3Fe4Be21.2 bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy.The mechanical relaxation behavior was analyzed ... The dynamic mechanical relaxation behavior of Ti36.2Zr30.3Cu8.3Fe4Be21.2 bulk metallic glass with good glass-forming ability was investigated by mechanical spectroscopy.The mechanical relaxation behavior was analyzed in the framework of quasi-point defects model.The experimental results demonstrate that the atomic mobility of the metallic glass is closely associated with the correlation factorχ.The physical aging below the glass transition temperature T g shows a non-Debye relaxation behavior,which could be well described by stretched Kohlrausch exponential equation.The Kohlrausch exponentβaging reflects the dynamic heterogeneities of the metallic glass.Both concentration of"defects"and atomic mobility decrease caused by the in situ successive heating during the mechanical spectroscopy experiments. 展开更多
关键词 Metallic GLASSES Mechanical RELAXATION Physical AGING Quasi-point defects
Joints of continuous carbon fiber reinforced lithium aluminosilicate glass ceramics matrix composites to Ti60 alloy brazed using Ti-Zr-Ni-Cu active alloy
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作者 Shengpeng HU Dongdong FENG +5 位作者 Long XIA Ke WANG Renwei LIU Zhentao XIA Hongwei NIU Xiaoguo SONG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第3期715-722,共8页
Continuous carbon fiber reinforced lithium aluminosilicate glass ceramics matrix composites(Cf/LAS composites) are joined to Ti60 alloy vacuum brazed using Ti-Zr-Ni-Cu brazing alloy. The effects of the brazing tempera... Continuous carbon fiber reinforced lithium aluminosilicate glass ceramics matrix composites(Cf/LAS composites) are joined to Ti60 alloy vacuum brazed using Ti-Zr-Ni-Cu brazing alloy. The effects of the brazing temperature on the interfacial microstructure and mechanical properties of brazed joints are investigated in details. The interfacial microstructure varies apparently with an increase of the brazing temperature. The thicknesses of the banded Ti solid solution(Ti(s, s)) and the reactive layer between Cf/LAS composites and the interlayer grow gradually. The mechanical properties of brazed joints increase firstly and then decrease with an increasing temperature. In addition, a joint that is brazed at 980℃ for 10 min shows the highest shear strength of$38.13 MPa. At the same time, the fracture paths of brazed joints also change as the temperature increases. When the brazing temperature is 950℃, the fracture position is in the TiC + ZrC +Ti2O + ZrSi2+ Ti5Si3 layer on the composite side. When the brazing temperature is 980℃, the fracture position is on the side of the braze seam(Ti, Zr)2(Ni, Cu), Ti2O + ZrSi2+ Ti5Si3 layer,and carbon fiber in the composite material. When the brazing temperature is 990℃, the fracture position is in the Ti2O + ZrSi2+ Ti5Si3 layer on the composite side and the carbon fiber in the composite material. 展开更多
关键词 BRAZING Composites Mechanical properties Microstructure TITANIUM alloys
Improvement of Mechanical Stability for Single Unit Recording Based on Skull Cap in Living Chinchilla 预览
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作者 Peng-yu REN Bo-wen +2 位作者 Shi-yao DONG Ming WU Peng HAN 《当代医学科学(英文)》 SCIE CAS 2019年第1期166-172,共7页
Three-point head fixation was constructed to provide mechanical stability for single unit recording(SUR)on vestibular sensory system in living chinchilla previously.However,it is no more qualified to this work when th... Three-point head fixation was constructed to provide mechanical stability for single unit recording(SUR)on vestibular sensory system in living chinchilla previously.However,it is no more qualified to this work when the stimulation intensity becomes large because of frequent unit losing and neuron damage,which strongly implies that the mechanical stability has been broken during the stimulation.Here,we constructed a novel hea0 fixation(skull cap assistant head fixation)provided by skull cap on the basis of three-point head fixation in order to improve the mechanical stability for SUR under the stimulation with large magnitude.The large area bone connection is the feature and advantage of this improved method,which directly fixes the tested local nervous tissue and microelectrode in an intact stable system through skull cap except two ear bars and a tube face mask.Our data exhibited that skull cap assistant head fixation could significantly improve the success rate of neural response activity recording in the population of semicircular canal neurons under the stimulation with large intensity(amplitudd 00 deg/s).Based on the analysis of neural response activity and noise base-line during stimulation,our data further indicated that this method could significantly improve the mechanical stability for SUR during high-speed motion stimulation on vestibular system in living chinchilla.Skull cap assistant head fixation extends the application of SUR on vestibular neuron in linear response range and provides a solid foundation for electrophysiological research on vestibular sensory system in fhrther studies. 展开更多
关键词 single unit recording SKULL CAP mechanical stability IMPROVEMENT semicircular CANAL NEURONS
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Influence of sigma phase on corrosion and mechanical properties of 2707 hyper-duplex stainless steel aged for short periods
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作者 Jian Wang Wan-li Chen +3 位作者 Hao-jie Meng Yi-shi Cui Cai-li Zhang Pei-de Han 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第5期452-461,共10页
2707 hyper-duplex stainless steels (HDSSs) contain high contents of alloying elements (Cr, Ni, Mo and N), which may shorten the incubation period and promote both nucleation and growth of sigma (σ) phase. 2707 HDSS w... 2707 hyper-duplex stainless steels (HDSSs) contain high contents of alloying elements (Cr, Ni, Mo and N), which may shorten the incubation period and promote both nucleation and growth of sigma (σ) phase. 2707 HDSS was first aged at different temperatures and periods of time for drawing the time-temperature-transformation profiles. The results identified the main precipitates as σ phase, with nose temperature of about 950℃. Also, 2707 specimen was aged at 950℃ for a short time, and the morphology, distribution and amount of σ phase were examined through the scanning electron microscope and X-ray diffraction,σ phase was initially formed at the boundaries of ferrite and austenite and then transformed through the eutectoid reaction (α→σ+γ2). Finally, the precipitation and growth of σ phase in 2707 steels aged at nose temperature for a short period reduced the corrosion resistance and deteriorated the mechanical properties, and the corresponding reason was further analyzed. 展开更多
关键词 Sigma phase CORROSION MECHANICAL property 2707 hyper-duplex STAINLESS steel Aging treatment
胶结充填体热-力-损伤行为模拟及试验分析 被引量:1
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作者 门瑞营 赵润康 《矿业研究与开发》 CAS 北大核心 2019年第1期22-27,共6页
通过数值模拟和试验分析相结合的方法对胶结充填体的热-力-损伤行为进行研究。在对比胶结充填体应力-应变曲线、损伤变量和温度演化的模型计算值和试验值,证明模型的有效性和适用性基础上,研究了不同水胶比和充填速率对其变形与损伤的... 通过数值模拟和试验分析相结合的方法对胶结充填体的热-力-损伤行为进行研究。在对比胶结充填体应力-应变曲线、损伤变量和温度演化的模型计算值和试验值,证明模型的有效性和适用性基础上,研究了不同水胶比和充填速率对其变形与损伤的影响。结果表明:提高胶结充填体的养护温度、水胶比和充填速率可以改善其力学性能,如峰值强度(弹性模量)的增加和损伤程度的降低。 展开更多
关键词 损伤 胶结充填体 数值模拟
Behavior of Nb influence on structure and properties of 30Cr13 cast martensitic stainless steel
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作者 Yang-fan Jin Tuo Zhang +1 位作者 Qi-yu Zang Yi-tao Yang 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第5期462-471,共10页
The microstructure, mechanical properties and corrosion resistance of 30Cr13 martensitic stainless steel (MSS) with different Nb contents were investigated by using the optical microscope, scanning electron microscope... The microstructure, mechanical properties and corrosion resistance of 30Cr13 martensitic stainless steel (MSS) with different Nb contents were investigated by using the optical microscope, scanning electron microscope, X-ray diffractometer, HRC hardness measurement apparatus and tensile testing machine. Nb was found to retard the formation of austenite and promote the precipitation of carbides by calculating. The results showed that the addition of 0.2 wt.% Nb elements could improve the strength and corrosion resistance of 30Cr13 martensitic stainless steels while the reduction in toughness was less because of the inhibited effect on Cr-rich carbides precipitation by Nb addition. Specially, M23C6-type carbides almost disappeared in 0.6Nb-MSS. Moreover, the main existent form of Nb element was NbC and the strong carbide-forming ability of Nb element increased the quantity of carbides with the morphology changing from sphericaltype to chain-type. 0.2Nb-MSS shows excellent strength, adequate toughness and sufficient corrosion resistance for the application. 展开更多
关键词 NIOBIUM ADDITION Martensitic STAINLESS steel Microstructure Mechanical property Corrosion resistance
Synthesis and characterization of the nanostructured solid solution with extended solubility of graphite in nickel by mechanical alloying 预览
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作者 Nitika Kundan Biswajit Parida +1 位作者 Anup Kumar Keshri Prathvi Raj Soni 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第8期1031-1037,共7页
In the present work,mechanical alloying of a powder mixture of nickel and graphite(up to 15wt%)was carried out in an attrition mill under a nitrogen atmosphere.The as-milled powders were characterized by scanning elec... In the present work,mechanical alloying of a powder mixture of nickel and graphite(up to 15wt%)was carried out in an attrition mill under a nitrogen atmosphere.The as-milled powders were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),and transmission electron microscopy(TEM).The 15wt%graphite dissolved into the nickel(exceeding the negligible solid solubility in the nickel–carbon system),thereby forming a supersaturated solid solution of graphite in a nickel matrix.The dissolved graphite occupied interstitial positions along the dislocation edges and at the grain-boundary regions.A three-step graphite dissolution mechanism has been proposed.The associated changes in the nickel lattice,such as changes in the crystallite size(62 to 43 nm),lattice strain(0.12%to 0.3%),and lattice parameter(0.3533 to 0.3586 nm),which led to the formation of the supersaturated solid solution,were also evaluated and discussed. 展开更多
关键词 Ni-C system mechanical ALLOYING supersaturated solid solution NANOSTRUCTURED POWDER
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Two methodological approaches to assess the seismic vulnerability of masonry bridges
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作者 Diego Maria Barbieri 《交通运输工程学报(英文版)》 CSCD 2019年第1期49-64,共16页
This work describes the seismic vulnerability assessment of a railway masonry arch bridge.Its conservation state is initially investigated by means of a thorough field and laboratory test campaign, comprising destruct... This work describes the seismic vulnerability assessment of a railway masonry arch bridge.Its conservation state is initially investigated by means of a thorough field and laboratory test campaign, comprising destructive and non-destructive tests. Two different methods are used to evaluate the bridge seismic vulnerability. The first method adopts a deterministic approach and corresponds to a single non-linear static analysis, performed as described in the Eurocodes. The second method employs a probabilistic approach and considers the variability of the involved mechanical parameters(structure geometry and properties of the building materials) and seismic parameters(intensity of the action and site conditions). This method associates the probabilistic values of ground acceleration exceedance to the estimated seismic vulnerability. This is shown by means of fragility curves, which allow to take into consideration the uncertainty of the various components involved in the definition of the seismic vulnerability and display the seismic damage scenarios. Currently no code requires to perform this calculation procedure. In addition,this work compares the values of masonry mechanical properties specified in the Eurocodes with those obtained in an extensive investigation campaign involving more than one hundred masonry bridges. Compressive strength and longitudinal elasticity modulus are the relevant mechanical parameters investigated. The outcomes of this research can contribute to the development of a more efficient maintenance system of the masonry bridges belonging to the railway network. This has an important role when it comes to establishing the priority order of assets intervention. 展开更多
关键词 Railway MASONRY ARCH BRIDGE BRIDGE maintenance and conservation MASONRY mechanical parameters NON-LINEAR static ANALYSIS Seismic FRAGILITY Finite element ANALYSIS
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