Z.T.Yu1
,
2)
,
L.Zhou1)
,
2)
,
J.Deng2) and H.C.Gu1) 1) College of MaterialScience and Engineering
,
Xi’an Jiaotong University
,
Xi’an 710049
,
China 2) NorthwestInstitute for Nonferrous Metal Research
,
P. O.Box 51
,
Xi’an 710016
,
China
金属学报(英文版)
Thelow cyclefatigue( LCF) propertiesof Ti 2 Al 2 5 Zralloytubeand rod specimens weredetermined at R.T. Thestress～strain curve equation under cyclic and monotonicloading andtherelation of totalstrain vsfatiguelife of Ti 2 Al 2 5Zr alloy were established. Theeffectsofstrain ratio R,strain amplitudeεaandspecimenshapeoncyclicdeformingbehavior and fatigueproperties were analyzed . The fatiguefracture features were also discussed ac cording as SEMobservation. The resultsshow , at R = 0 1 ,thecyclicstress straincurvesof Ti 2 Al 2 5Zr alloytube and rodspecimensappear ascyclesoftening. When Ris 1 ,itsrodspecimen behavesascyclesoftening;atlow εavalues; whereasitbehavesascyclehardeningat high εa values. The LCFproperties determined withtubespecimen islower apparentlythanthat withrod one. Thereare muchirregularrecrystallineconvexin LCFfracturesof Ti 2 Al 2 5Zr alloytubeand rodspecimens, and muchsecondarycracks,fatiguestriationsand holes alsoexistamongthem .
关键词:
Ti 2 Al 2 5 Zralloy
,
null
,
null
李梦佳
,
陈普会
,
孔斌
,
彭涛
,
姚正兰
,
邱学仕
复合材料学报
doi:10.13801/j.cnki.fhclxb.20150930.002
在关于拉脱载荷下Z-pin增强T型接头的有限元模拟方法基础上,通过对2组蒙皮厚度分别为7.2 mm和4.0 mm的试验件的试验结果进行分析,研究了T型接头蒙皮厚度对 Z-pin增强效果的影响。结果表明：Z-pin增强效果随着蒙皮厚度的减小而增大。蒙皮厚度大于5 mm,Z-pin不能提高结构的最大承载能力,但可显著提高结构首次掉载后的承载性能,使T型接头在较大的加载位移下仍保持较高的承载能力；无论蒙皮厚薄,结构首次掉载后,各Z-pin增强T型接头可达到的载荷平台是相当的,且该载荷平台随蒙皮的变厚有降低的趋势。
关键词:
复合材料
,
T型接头
,
Z-pin
,
蒙皮厚度
,
有限元模拟
李梦佳
,
陈普会
,
孔斌
,
彭涛
,
姚正兰
,
邱学仕
复合材料学报
doi:10.13801/j.cnki.fhclxb.201502.002
利用二维平面应变模型对Z-pin增强T型接头试样进行失效分析,采用内聚力模型模拟界面的破坏情况,通过在分层的上下界面加入非线性弹簧元模拟Z-pin的增强作用,非线性弹簧元的力学性能(桥联律)由细观力学方法获得,数值结果与试验值吻合较好.在已验证有限元方法的基础上,研究了Z-pin直径、密度及植入角度等对T型接头拉脱承载能力的影响.结果表明:Z-pin增强可显著提高T型接头的拉脱承载能力,与未Z-pin增强的T型接头相比,Z-pin增强明显延缓了掉载;T型接头的拉脱承载能力随Z-pin直径和密度的增加而增大,随植入角度的增大而减小;在所研究的角度范围内,当植入角度为60°时,T型接头的拉脱承载能力最好;Z-pin直径和密度对拉脱承载能力的影响远比植入角度的影响显著.
关键词:
复合材料
,
T型接头
,
Z-pin
,
非线性弹簧
,
桥联律
李成虎
,
燕瑛
复合材料学报
提出了基于z-pin桥联力试验的z-pin增强复合材料T型接头层间性能的模拟方法.每根z-pin的作用有两部分:增加了分层的张开阻力与剪切阻力.在有限元模拟中通过在相应的节点上加两个方向(竖直方向和水平方向)的非线性弹簧模拟张开阻力和剪切阻力.通过张开型z-pin桥联力试验和剪切型z-pin桥联力试验得到两条力-位移曲线,再把曲线各自赋予到所有竖直非线性弹簧和水平非线性弹簧,从而模拟z-pin对复合材料T型接头层间性能的增强效果.在T型接头拉拔试验模拟分析中,研究了不同跨距和不同z-pin间距对拉拔力的影响.模拟分析表明跨距对拉脱位移影响较大,z-pin间距对最大拉拔力影响较大.
关键词:
z-pin
,
复合材料
,
z-pin桥联力
,
张开型
,
剪切型
,
非线性弹簧
张立春
,
何安强
,
吴玉琨
,
叶恒强
,
张永昌
金属学报
利用高分辨电镜(HRTEM)和常规电子显微术研究了快速凝固Al-Li-Cu—Mg—Zr合金中Z相和T相的结构关系,发现两相间两种确定的晶体学取向关系,并以此为依据解释了Z相和T相的某些结构缺陷两相的结构有密切关联,其中一相中缺陷的扩展会导致另一相的形成
关键词:
Al-Li-Cu-Mg-Zr合金
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Z hexagonal phase
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T f.c.c. phase
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shear structure
Chinese Physics Letters
The magnetic properties of 1 T-TaS2 and 1 T-Fe-0.07 Ta-0.93 S-2 have been studied, Experimental results show that the phase transition temperature of 1 T-TaS2 is a function of the magnetic field, At low temperatures, both compounds are in a mixed state of charge density wave -spin density wave due to the coherent superposition of antiferromagnetic coupling.
关键词:
density
Physical Review B
The magnetic properties and phase transitions of 1T-TaS2 and 1T-Fe0.07Ta0.93S2 have been studied in the interval of 1.5-300 K and over the range of 100 Oe-60 kOe. Experimental results show that at high temperatures the compounds are in a diamagnetic state and the commensurate-charge-density-wave-triclinic-nearly-commensurate transition temperature of 1T-TaS2 decreases with increasing magnetic field. The amount of variation is a function of the magnetic field. At low temperatures both 1T-TaS2 and 1T-Fe0.07Ta0.93S2 are in a paramagnetic state owing to the localized moments that come from the single Anderson-Mott localization state. The curves of magnetization versus temperature do not follow the Curie law or Curie-Weiss law, but can be described fairly well as M = M(0) + gamma T--n. The fitting parameters of experimental curves show that a part of the neighboring moment appears as antiferromagnetic coupling due to exchange interaction between the moments. The magnetic-field dependence of magnetization exhibits a complicated feature at low temperature. It shows that the compounds may undergo a phase transition at the maximum value of magnetization and then they are probably in a mixed charge-density-wave-spin-density-wave (CDW-SDW) state or SDW state due to the coherent superposition of the antiferromagnetic coupling.
关键词:
metal-insulator-transition;density-wave domains;high magnetic-fields;charge-density;doped 1t-tas2;coexistence;microscopy;systems;silicon;2h-tas2
陈耿
,
谢建良
,
黄鹏
功能材料
采用陶瓷工艺制备C02Z(Ba3(Co0.4Zn0.6)2Fe23.4O41)和BaM(BaFi1.4Co1.4Fe9.2O19)六角铁氧体,二次球磨时掺杂少量BST(BaSrTiO3)铁电材料,对比研究了BST掺杂对Z型和M型铁氧体在1MHz～1GHz频率范围内相对复磁导率(μr=μr1-iμr")的影响.BST的掺杂使Z型铁氧体μr增大,共振频率点移向低频;使M型铁氧体的μr减小,共振频率点移向高频.通过对其微观结构和磁参数的测试分析,讨论了BST掺杂对Z型和M型铁氧体复磁导率不同影响的作用机理.
关键词:
Z型六角铁氧体
,
M型六角铁氧体
,
磁晶各向异性场
,
相对复磁导率
Communications in Theoretical Physics
For the first time, by taking into account all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as all the levels and the admixtures of wavefunctions within d(3) electronic configuration, the values of parameters in expressions of Raman and optical-branch terms of thermal shifts (TS) due to EPI for three levels, T-4(2) band and T-4(1) band of ruby have been evaluated; the contributions to TS of T-4(2) and T-4(1) broad bands from thermal expansion have also been. calculated; and then, the TS of the peak energies of 'T2 and 4 Ti broad bands have been calculated. The results are in satisfactory agreement with observed data. The values of single-electron reduced matrix elements representing the strengths of EPI of T-4(2) and T-4(1) bands have respectively been determined. For TS of the peak energies of T-4(2) and T-4(1) bands, it is found that the contribution to TS from the second-order term in EPI Hamiltonian is dominant; TS due to EPI of acoustic branches are over two times as much as those of optical branches, and both of them increase rapidly with temperature; the neighbor-level term is insignificant; the contribution to TS from thermal expansion is specially important, and all the three terms of TS of T-4(2) or T-4(1) band axe red shifts.
关键词:
crystal fields;optical spectral bands;electron-phonon interaction;thermal expansion;thermal shift;theoretical calculations;high-pressure;field;spectroscopy;spectra
