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A practical model for efficient anti-fatigue design and selection of metallic materials:Ⅰ.Model building and fatigue strength prediction

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Journal of Materials Science & Technology 2021年第11期70卷 233-249页

作者： R.Liu p.zhang Z.J.zhang B.Wang Z.F.zhang Laboratory of Fatigue and Fracture for Materials Shi-changxu Innovation Center for Advanced MaterialsInstitute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China

The high cost and low efficiency of fatigue tests are bottleneck problem for the anti-fatigue design of metallic *** this problem,a theoretical fatigue model is proposed in this study,the possible applications have also been *** results would be introduced in two serial papers,in which the first paper focuses on the model building and the applications on fatigue strength prediction;the second paper put emphasis on the influencing factors of the model parameters and the applications on fatigue strength *** this first paper,a theoretical model is proposed considering both the strength and plastic restrictions of fatigue *** the model builds up a brief relationship among yield strength(Y),tensile strength(T)and fatigue strength(F),it is named as the Y-T-F *** the verification with fatigue strength data covering various kinds of metallic materials and loading conditions,this Y-T-F model exhibits both generality and *** the Y-T-F model,the efficient fatigue strength prediction could be conducted by brief linear fitting and calculation,just through yield strength,tensile strength and several known fatigue strength ***,through its deduced Y-F model,the analytical formula of fatigue strength continuously changing with materials strengthening can be obtained,as well as the maximum value of fatigue strength and corresponding critical yield *** summary,the Y-T-F model would be useful for reducing the fatigue tests,thus providing new possibilities on the efficient anti-fatigue design and selection of metallic materials.

关键词： Yield strength Tensile strength plasticity Fatigue strength Anti-fatigue design

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Numerical modeling for a simulated rockburst experiment using LS-DYNA

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Underground Space 2021年第2期6卷 153-162页

作者： C.p.Yi E.Nordlund p.zhang S.Warema S.Shirzadegan Division of Mining and Rock Mechanics Lulea University of TechnologySweden

Ground support systems are commonly used to mitigate the potential consequences of rockburst in burst prone *** assess the capacity of ground support systems when subjected to dynamic loading,simulated rockburst tests using blasting were conducted at the Kiruna *** this study,a numerical simulation for one of the field tests was conducted using the LS-DYNA code to investigate the dynamic response of the ground support systems including shotcrete and *** numerical results showed a similar particle vibration pattern and a crack pattern to those of the field *** effects of the detonator position and the charge configuration on the dynamic response of ground support systems are also *** results indicated that the peak particle vibrations on the tested panel increase along the direction of detonation *** is difficult to use different charge concentrations in one borehole to investigate the effect of different dynamic loads on the dynamic response of support *** results also indicated that 2D numerical modeling for simulated rockburst experiments could overestimate the dynamic response of ground support systems.

关键词： Simulated rockburst experiments Ground support systems Numerical modeling

Longwall mining,shale gas production,and underground miner safety and health

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International Journal of Mining Science and Technology 2021年第3期31卷 523-529页

作者： D.W.H.Su p.zhang H.Dougherty M.Van Dyke R.Kimutis Center for Disease Control and prevention(CDC) National Institute for Occupational Safety and Health(NIOSH)Pittsburgh Mining Research Division(PMRD)PittsburghPA 15236USA

This paper presents the results of a unique study conducted by the National Institute for Occupational Safety and Health(NIOSH)from 2016 to 2019 to evaluate the effects of longwall-induced subsurface deformations on shale gas well casing integrity and underground miner safety and *** both deep-cover and shallow-cover instrumentation sites,surface subsidence measurements,subsurface inplace inclinometer measurements,and underground pillar pressure measurements were conducted as longwall panels were *** of the deep-cover and shallow-cover test site results with those from a similar study under medium cover reveal an interesting longwall-induced response *** shallow and medium covers,measured horizontal displacements within the abutment pillar are one order of magnitude higher than those measured under deep *** the other hand,measured vertical compressions under deep cover are one order of magnitude higher than those under shallow and medium ***,FLAC3 Dsimulations of the casings indicate that,in all three cases,the p-110 production casings remain intact under longwall-induced deformations and compressions,which has serious implications for future mine design in areas where shale gas wells have been drilled ahead of mining.

关键词： Longwall Mining Coal Gas Miner Safety Health

Enhancing the high-temperature creep properties of Mo alloys via nanosized La_(2)O_(3) particle addition

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Journal of Materials Science & Technology 2022年第35期130卷 53-63页

作者： p.M.Cheng C.Yang p.zhang J.Y.zhang H.Wang J.Kuang G.Liu J.Sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Molybdenum(Mo) alloys with different La_(2)O_(3)particle additions(0.6,0.9,1.5 wt.%) were prepared by powder metallurgy to investigate the effect of La_(2)O_(3)particles on microstructural evolution and creep behavior of the *** Mo,annealed at 1500℃ for 1 h,presented a fully recrystallized microstructure characterized by equiaxed *** alloys doped with La_(2)O_(3)particles(Mo-La_(2)O_(3)alloys),on the other hand,exhibited fibrous grains elongated in the rolling direction of the *** contrast to the shape of the grains,the average grain size of the alloys was found to be insensitive to the addition of La_(2)O_(3)*** La_(2)O_(3)particles with diameters ranging from 65 to 75 nm were distributed within the grain *** creep tests showed that dislocation creep was the predominant deformation mode at intermediate creep rate(10^(-7)s^(-1)-10^(-4)s^(-1)) in the present *** creep stress exponent and activation energy were found to decrease with increasing temperature,particularly within the low creep rate regime(pparent stress exponent and activation energy than pure Mo.A creep constitutive model based on the interaction between particles and dislocations was utilized to rationalize the nanoparticle-improved creep *** was demonstrated that low relaxed efficiency of dislocation line energy,which is responsible for an enhanced climb resistance of dislocations,is the major creep strengthening mechanism in the Mo-La_(2)O_(3)*** addition,the area reduction and creep fracture mode of the Mo-La_(2)O_(3)alloys were found to be a function of the creep rate and temperature,which can be explained by the effect of the two parameters on the creep and fracture mechanisms.

关键词： Mo alloys Nanosized particles Creep strength Deformation and fracture

High-temperature fatigue strength of grain boundaries with different misorientations in nickel-based superalloy bicrystals

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Journal of Materials Science & Technology 2023年第23期154卷 94-106页

作者： D.F.Shi Z.J.zhang Y.H.Yang Y.Z.Zhou R.Liu p.zhang Z.F.zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Shenyang 110016 China

Nickel-based single-crystal superalloys are widely used in the manufacture of aeroengine turbine vanes for their excellent high-temperature performance. Low-angle grain boundaries (LAGBs) will be generated inevitably during their manufacture, which are often characterized by grain boundary misorientation (GBM) and will weaken the mechanical properties of superalloys. However, the relationship between GBM and the fatigue properties of superalloys at elevated temperatures has seldom been investigated due to the difficulty in the sample preparation and experiment process. Based on six kinds of bicrystals with different tilt LAGBs made by a second-generation single-crystal superalloy, the effects of misorientation on the grain boundary microstructure and fatigue properties (980 °C) of superalloys were studied systematically in this work. It is found that, with the increase of GBM, the GB precipitates combined with the cast micropores increase monotonically, accordingly both the fatigue life and fatigue strength decrease successively. Fatigue fracture observations show that the cracks of all the bicrystals initiated from the cast micropores at GBs, and then propagated along the GBs. Therefore, the coupling effect of cast micropores and GBM on the fatigue damage mechanisms of the bicrystals are evaluated according to their hindering degrees on the piled-up dislocations. Combining with a hysteresis energy model, a quantitative fatigue strength prediction model of superalloys is established and is well verified by abundant experimental data. This study could provide guidance for fatigue performance prediction and structural design of superalloys.

关键词： Superalloys Bicrystals Grain boundary misorientation Fatigue strength Fatigue crack

STRESS CORROSION CRACKING IN 16NiCo STEEL

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Acta Metallurgica Sinica(English Letters) 1997年第3期10卷 256-262页

作者： p.zhang B.Z Guand B. Ling (Beijing Institute of Aeronautical Materials, Beijing 100095, China) Beijing Inst of Aeronautical Materials Beijing China

The dst of tempering temperature on strength, impact toughness, fracture toughness and stress corrosion cracking (SCC) behavior of 16NiCo Steel in an aqueons solutiou of 3.5 pct NaCl was stndied. The test compromise between strength, tonghness, and SCC resistance was obtained after 510℃ tempering. Under these conditions, KISCC is~75 Mpam with fracture toughness of~75 Mpam, impact toughness of~150J/cm2 and a gield strength of~1580 Mpa. The improved stress corrosion crack-ing resistance at 510℃ tempering may be related to the loss of stress resulting from M2C/matrix coherency and the recovery of the dislocalion substrvcture. These would lead to a decreased concentration of hydrogen.

关键词： streas corrosion secondary hardeing 16NiCo steel

predicting the variation of stacking fault energy for binary Cu alloys by first-principles calculations

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Journal of Materials Science & Technology 2020年第18期52卷 61-65页

作者： T.Cai K.Q.Li Z.J.zhang p.zhang R.Liu J.B.Yang Z.F.zhang Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan province College of Advanced Materials and EnergyInstitute of Surface Micro and Nano MaterialsXuchang UniversityXuchang 461000China Laboratory of Fatigue and Fracture for Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

The variation of stacking fault energy(SFE)in a number of binary Cu alloys is predicted through considering the Suzuki segregation by the full potential linearly augmented plane wave(FpLApW)*** calculated results show that some solute atoms(Mg,Al,Si,Zn,Ga,Ge,Cd,Sn,and pb),which prefer to form the Suzuki segregation,may decrease the value of SFE;while the others(Ti,Mn,Fe,Ni,Zr,Ag,and Au),which do not cause the Suzuki segregation may not decrease the ***,it is interesting to find that the former alloying elements are located on the right of Cu group while the latter on the left of Cu group in the periodic table of *** intrinsic reasons for the new findings can be traced down to the valences electronic structure of solute and Cu atoms,i.e.,the similarity of valence electronic structure between solute and Cu atoms increases the value of SFE,while the difference decreases the value of SFE.

关键词： Cu-alloy Deformation behavior First-principles calculation Stacking fault energy

Examining the effect of the aging state on strength and plasticity of wrought aluminum alloys

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Journal of Materials Science & Technology 2022年第27期122卷 54-67页

作者： Z.Qu Z.J.zhang J.X.Yan p.zhang B.S.Gong S.L.Lu Z.F.zhang T.G.Langdon Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Department of Mechanical Engineering University of SouthamptonSouthampton SO171BJUnited Kingdom

A general rule of strength and plasticity was proposed for three typical wrought Al alloys(2xxx,6xxx,and 7xxx)subjected to different aging *** of the work-hardening processes and dislocation configurations in tensile and compressive testing reveal that this general rule arises because there is a common mechanism for these three kinds of wrought alloys whereby the tendency for cross-slip increases monotonously with aging *** analyzing the strain hardening exponent and the stacking fault energy,it is demonstrated that the change in the dislocation slip mode is attributed mainly to the formation of second phases rather than to the matrix ***,a new work-hardening model was proposed for wrought Al alloys containing second phases and this explains the interaction between dislocations and second phases and other relevant experimental *** work is therefore beneficial for quantitatively investigating and optimizing the strength and plasticity of wrought aluminum alloys.

关键词： Wrought aluminum alloy Strength and plasticity Work hardening Dislocation slip mode Second phase

Design and optimization of the composition and mechanical properties for non-equiatomic CoCrNi medium-entropy alloys

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Journal of Materials Science & Technology 2023年第8期139卷 232-244页

作者： J.X.Yan Z.J.zhang p.zhang J.H.Liu H.Yu Q.M.Hu J.B.Yang Z.F.zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Chongqing Jiaotong UniversityChongqing 400074China chool of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China School of Information Science and Engineering Shenyang University of TechnologyShenyang 111003China

The development of multi-principal element alloys(MpEAs,also called as high-or medium-entropy al-loys,HEAs/MEAs)provides tremendous possibilities for materials ***,designing MpEAs with desirable mechanical properties confronts great challenges due to their vast composition *** this work,we provide an essential criterion to efficiently screen the CoCrNi MEAs with outstanding strength-ductility *** negative Gibbs free energy difference△E_(FCC-BCC)between the face-centered cubic(FCC)and body-centered cubic(BCC)phases,the enhancement of shear modulus G and the decline of stacking fault energy(SFE)γ_(isf)are combined as three requisites to improve the FCC phase stability,yield strength,deformation mechanisms,work-hardening ability and ductility in the *** effects of chemical composition on△E_(FCC-BCC),G andγisf were investigated with the first principles calculations for Co_(x)Cr_(33)Ni_(67-x),Co_(33)Cr_(y)Ni_(67-y)and Co_(z)Cr_(66-z)Ni_(34)(0≤x,y≤67 and 0≤z≤66)*** on the essential criterion and the calculation results,the composition space that displays the neg-ative Gibbs free energy difference△E_(FCC-BCC),highest shear modulus G and lowest SFEγ_(isf)was screened with the target on the combination of high strength and excellent *** this context,the optimal composition space of Co-Cr-Ni alloys was predicted as 60 at.%-67 at.%Co,30 at.%-35 at.%Cr and 0 at.%-6 at.%Ni,which coincides well with the previous experimental evidence for Co_(55)Cr_(40)Ni_(5)*** valid-ity of essential criterion is further proved after systematic comparison with numerous experimental data,which demonstrates that the essential criterion can provide significant guidance for the quick exploitation of strong and ductile MEAs and promote the development and application of MpEAs.

关键词： Medium-entropy alloys First-principles calculations phase stability Stacking-fault energy Strength Ductility