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Journal of Iron and Steel Research International 2022年第2期29卷 207-214页

作者： Zhen-bao Liu Zhe Yang Jian-xiong Liang Zhi-yong Yang Guang-min Sheng Division of Special Steels Central Iron and Steel Research Institute(CISRI)Beijing100081China School of Material Science and Engineering Chongqing UniversityChongqing400044China

Multiple precipitating species in a 2.2 GPa grade precipitation-hardened martensitic stainless steel with balanced ductility were characterized at atomic scale by atom probe *** results indicated that the clustering of solute atoms was promoted with progressive aging treatments.(Cr,Mo)-rich carbide(M_(2)C)precipitated at the linear dislocations in the as-aged *** segregation of Cr,Mo,and C at phase boundaries favored the precipitation of carbide and caused the formation of Cr-lean *** decomposition of martensitic matrix during aging led to the substantial precipitation of fine Cr-rich(α′Cr)*** with the first aging treated samples,a synergistic enhancement of both strength and ductility of the secondary aging treated(SAT)samples was primarily ascribed to the enhanced precipitation of Cr-rich ***,Ni-rich filmy reversed austenite precipitated at the lath boundary,which was beneficial to the ductility of SAT samples.

关键词： Aging treatment Nanoprecipitate Atom probe spinodal decomposition Precipitation-hardened martensitic stainless steel

Influence of quenching medium on the dendrite morphology,hardness,and tribological behaviour of cast Cu-Ni-Sn spinodal alloy for defence application

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Defence Technology（防务技术） 2023年第12期30卷 83-100页

作者： Bipin Sankar Karthik V Shankar Vamu Sunil Hemanth Kashyap S Nikhil Nair Adarsh A.Nair Abhinav P M Department of Mechanical Engineering Amrita Vishwa VidyapeethamAmritapuriIndia

Cu-Ni-Sn spinodal alloys(spinodal bronze)are potential materials with robust applications in components associated with defence applications like bearings,propellers,bushes,and shafts of heavily loaded aircraft,off-road vehicles,and *** paper presents a comparative study using water,Brine solution,and SAE 40 oil as the quenching media in regular bronze(Cu-6Sn)and spinodal bronze(Cu-9Ni-6Sn)*** analysis was conducted by optical microscopy,transmission electron microscopy(TEM),and X-ray diffraction technique(XRD)on bronze and spinodal bronze samples immersed in the three different quenching media to understand the grain size and hardness values *** analysis was performed to analyze the effect of quenching media on the wear aspects of bronze and spinodal bronze *** hardness value of the brine-aged spinodal bronze samples was as high as 320 Hv,and the grain size was very low in the range of 60μm.A quantitative comparison between brine-aged regular bronze and brine-aged spinodal bronze showed that the hardness(Hv)was almost 80%higher for brine-aged spinodal ***,the grain size was approximately 30%finer for spinodal bronze when compared with regular *** the load was increased in spinodal bronze samples,there was an initial dip in wear rate followed by a marginal *** was a steady increase in friction coefficient with a rise in load for brine-aged regular bronze and spinodal bronze *** results indicate that brine solution is the most effective quenching medium for cast Cu-Ni-Sn spinodal alloys.

关键词： Quenching Water Brine SAE 40 oil Grain size Hardness Wear rate spinodal decomposition CuSn spinodal alloy CuNiSn

Oxygen-assisted spinodal structure achieves 1.5 GPa yield strength in a ductile refractory high-entropy alloy

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Journal of Materials Science & Technology 2023年第26期157卷 11-20页

作者： Dingcong Cui Yuyu Zhang Linxiang Liu Yue Li Lei Wang Zhijun Wang Junjie Li Jincheng Wang Feng He State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China

Refractory high-entropy alloys(RHEAs)with room-temperature ductility are drawing growing attention for potential high-temperature ***,the most widely used metallurgical mechanisms appear weak in optimizing their strength and ***,we report that the nanoscale spinodal struc-ture in Ti_(41)V_(27)Hf_(15)Nb_(15)O_(2)leads to the highest tensile yield strength(∼1.5 GPa)among the existing RHEAs and good elongation of∼12%.With the aid of thermodynamic calculations,we show that oxygen plays a dominant role in controlling the formation of the spinodal structure by influencing the spinodal gap of the Ti-V-Hf-Nb *** the atomic structure of the spinodal structure(β+β^(∗)),we showed that the large lattice misfit of the spinodal phases is mainly responsible for the excellent strengthen-ing effect while the planar to wavy dislocation glide mode transition accounts for the retained *** work provides a novel strategy to improve the mechanical properties of the RHEAs and deepens the understanding of their phase stabilities.

关键词： High entropy alloys spinodal decomposition Strengthening mechanisms

Effect of Cu on Discontinuous Precipitation of a Symmetrical AlZn Alloy

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Journal of Materials Science & Technology 2005年第2期21卷 215-218页

作者： Shiming HAO, Yuping REN, Dapeng WANG, Danyang DONG and ffongxiao LI College of Materials and Metallurgy, Northeastern University, Shenyang 110004, China Coll. of Mat. and Metall. Northeastern Univ. Shenyang 110004 China

The effect of Cu additions on discontinuous precipitation of AlZn alloy were studied with optical microscopy, scanning electron microscopy and X-ray diffraction. It is found that the effect of addition of 2 at. pct Cu on cellular nucleation site is not remarkable, while the effect of aging temperature on cellular nucleation site of AlZn and AIZn-2Cu alloys is fairly obvious. The cell growth rate of discontinuous precipitation of AlZn alloy is remarkably accelerated with the addition of 2 at. pct Cu. The discontinuous precipitation microstructure of AlZn alloy is not apparently affected with the addition of 2 at. pct Cu and the cellular front is still fine microstructure of spinodal decomposition. The phase constituents consist of a fcc Al-rich phase, a hcp Zn-rich phase and a CuZn4 phase. The transformation rate of discontinuous precipitation of AlZn alloy is remarkably accelerated with the addition of 2 at. pct Cu.

关键词： Al-Zn(-Cu) alloy spinodal decomposition Discontinuous precipitation Transformation rate

Microstructures of spinodal phases in Cu-15Ni-8Sn alloy

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Journal of University of Science and Technology Beijing 2005年第3期12卷 243-247页

作者： YanhuiWang MingpuWang BinHong SchoolofMaterialScienceandEngineering CentralSouthUniversityChangsha410083China

The microstructures of spinodal phases in Cu-15Ni-8Sn alloy were studied by TEM. It was found that when the alloy is completely in a as-quenched state, spinodal decomposition is quick. Ordering appears after spinodal decomposition. The ordered phase with DO22 structure has three variants obtained from coarsening spinodal structure. The reason of ordering appeared after spinodal decomposition is that the content of solute atoms needed by ordering is higher than the average, which can be reached by the composition fluctuation of spinodal decomposition. It was speculated that the morphology of the ordered phase is needle-like.

关键词： Cu-15Ni-8Sn alloy spinodal decomposition DO22 ordering variant

Origin of Ordering Coupled Tweed Microstructures in Alloys with Large Atomic Size Factors

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Journal of Materials Science & Technology 1996年第3期12卷 166-174页

作者： Ren, XB Wang, XT Shimizu, K Tadaki, T XIAN JIAOTONG UNIV COLL MAT SCI & ENGNXIAN 710049PEOPLES R CHINA OSAKA UNIV INST SCI & IND RESIBARAKIOSAKA 567JAPAN

A theoretical study is developed on the evolution and mechanism of an ordering coupled phase separation, and on the origin of a resultant tweed microstructure. It is found that long-range elastic interaction among atoms with different atomic sizes plays a key role in the phase separation, and that the evolution of the phase separation is very similar to that of conventional spinodal decomposition except that the separation is dependent on an elastic interaction ordering (EIO). This ''EIO coupled spinodal decomposition'' is shown to exhibit a periodical or tweed microstructure being accompanied by an EIO. It is also found that a large atomic size factor yields a large positive contribution of EIO to spinodal decomposition. Generally, it is thermodynamically and kinetically favorable for the EIO to precede the onset of spinodal decomposition, though the former is not separable from the latter as a whole. We suggest that an initially disordered solid solution undergoes an EIO first, and then the partially ordered solid solution starts to decompose via a spinodal mechanism. Solute-enriched regions increase their degree of order along with an increase in solute content, and solute-depleted regions decrease their degree of order together with a decrease of solute content. The final microstructure is characterized by a periodical array of highly ordered solute-enriched regions and nearly disordered solute-depleted regions. The notion of EIO coupled spinodal decomposition is in general agreement with the transformation behaviour of a large number of alloy systems.

关键词： spinodal decomposition TITANIUM ALLOYS TI ALLOYS TRANSFORMATIONS NICKEL LI

Microstructural Changes of Cu-Ni-Si Alloy during Aging

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Journal of Materials Science & Technology 2004年第1期20卷 99-102页

作者： QimingDONG DongmeiZHAO PingLIU BuxiKANG JinliangHUANG DepartmentofMaterialsEngineering HenanUniversityofScienceandTechnologyLuoyang471003China DepartmentofScientificResearch LuoyangUniversityLuoyang471000China

Age hardening in Cu-3.2Ni-0.75Si (wt pct) and Cu-1.0Ni-0.25Si (wt pct) alloys from 723 to 823 K is studied. After an incubation period strengthening appears which is due to precipitates in the ***-0.25Si (wt pct) alloy. On other hand an immediate increase of the yield strength characterizes the aging of the alloy. This is followed by the regions of constant yield strength and further by a peak. The microstructure of the alloy was studied by, means of transmission electron microscope (TEM) and X-ray diffraction (XRD). spinodal decomposition takes place followed by nucleation of the ordering coherent (Cu,Ni)3Si particles, further precipitation annealing coherent δ-Ni2Si nucleated within the (Cu,Ni)3Si particle. Any change of the yield strength can be described by an adequate change of the structure in the sample. The nature of the aging curves with a 'plateau' is discussed. The formulas of Ashby and Labusch can be used to explain the precipitation.

关键词： Copper alloy Transformation Ageing spinodal decomposition Ordering Yield strength

ON spinodal BOUNDARIES OF Al-Li ALLOYS

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Acta Metallurgica Sinica(English Letters) 1995年第1期8卷 41-46页

作者： Wei Yinghui Wang Xiaotian Xi'an Jiaotong Univ Xi'an China

The spinodal decomposition can occur in Al-Li alloys containing 5.8-14.2 at.% Li at room temperature. The modutated structure wavelength is approximately 3.1 nm for com mercial Al-LI alloys. The limit composition of t... 详细信息

关键词： Al-Li alloy spinodal decomposition regular solution

Solidified morphology and mechanism of bulk nanocrystalline Fe80P13C7 alloy at isothermal undercooling

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Science China Technological Sciences 2014年第8期57卷 1626-1630页

作者： WANG Tuo LI Qiang School of Physics Science and Technology Xinjiang University

The molten Fe80P13C7 alloys can achieve a large undercooling up to 320 K by fluxing *** the help of fluxing technique,the molten Fe80P13C7 alloys can be solidified at different undercooling(△T)through isothermal undercooling *** is indicated that the microstructure of the solidified Fe80P13C7 alloy specimens is refined significantly with the increasing undercooling and the grain size is about 20μm,10μm,200 nm and 70 nm for△T=50 K,150 K,250 K and 320 K,*** solidification morphologies of the solidified Fe80P13C7 alloy specimens under different undercooling are quite ***△T=50 K,it presents a traditional solidification microstructure under a undercooling condition,composed of the primary dendrite and anomalous eutectic within the ***△T=150 K,a cell-like solidification morphology can be found,which can be proposed to be formed based on the nucleation and growth of spinodal decomposition ***△T=250 K,there is a strong direction of the solidification under an optical micrograph,two zones can be divided,and the microstructure of each zone presents a network which results from a liquid spinodal ***△T=320 K,the microstructure presents a random network *** test shows that the hardness of the solidified specimens increases with the undercooling.

关键词： Fe-P-C alloy undercooling spinodal decomposition nanocrystalline

Lattice Boltzmann Simulation of 3D Nematic Liquid Crystal near Phase Transition

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Communications in Theoretical Physics 2002年第2期37卷 253-256页

作者： ZHANGJun TAORui－Bao DepartmentofPhysics FudanUniversityShanghai200433China

Phase transition between nematic and isotropic liquid crystal is a very weak first order phase *** avoid to use the normal Landau-de Gennes's free energy that reduces a strong first order transition, and set up adata base of free energy calculated by means of Tao-Sheng Lin's extended molecular field theory that can explain theexperiments of the equilibrium properties of nematic liquid crystal very well. Then we use the free energy method oflattice Boltzmann developed by Oxford group to study the phase decomposition, pattern formation in the flow of theliquid crystal near transition temperature.

关键词： nematic liquid crystal lattice Boltzmann spinodal decomposition