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Mn对Fe3Al合金室温力学性能的影响 总被引:1,自引:0,他引:1
Fe3Al金属间化合物具有抗氧化耐腐蚀性良,比强度高和成本低等特点,从而具有可观的工程应用前景。对这种材料目前国内研究的热点之一是改善其室温塑性。改善Fe3Al合金室温塑性的一个重要途径是合金化,这是因为Fe3Al合金有序结构的成分变化范围较宽,适于通过合金化来改善其性能,有报道表明,在Fe3Al合金中加入Cr可有效地提高室温塑性,但会使屈服强度有所下降,本文在加Cr的研究基础上,研究了Mn对Fe 相似文献
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Zr对Ni3Al晶界及力学性能的影响 总被引:4,自引:0,他引:4
对不同Zr含量Ni3Al的力学性能及晶界的研究结果表明:随Zr含量的增加,合金的屈服强度和抗张强度不断提高;当Zr≤0.7at.-%时,塑性随Zr含量的增加而提高;但Zr含量达1.2at.-%时,Zr的增塑效果下降.Auger能谱分析表明:Zr在晶界有偏聚,偏聚因子约为3.断口观察显示:不含Zr或Zr含量为1.2at.-%的Ni-24.0Al合金均为沿晶断裂,其余含Zr合金的断裂方式为穿晶、沿晶混合断裂.这表明:含Zr的Ni3Al塑性和Zr在晶界的偏聚有密切关系. 相似文献
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本文研究了在950℃空气中,表面涂Na_2SO_4盐膜的条件下,NiAl,NiAl-20%Fe及渗铝后的高温热腐蚀行为。在热腐蚀过程中,NiAl合金表面能形成Al_2O_3膜,显示出一定的耐蚀性能。但Al_2O_3膜易开裂,Al_2O_3膜的溶解及开裂会引发合金发生快速热腐蚀;20%Fe的加入则使NiAl合金的耐蚀性能显著变差,合金表面不能形成单一的Al_2O_3膜;渗铝处理可以明显提高NiAl-20%Fe合金的耐蚀性能,且渗铝涂层的耐蚀性能优于NiAl合金,这与铝化物涂层中的Al含量较高,Al_2O_3膜的开裂倾向较小有关。 相似文献
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Sc对Al—Li—Cu—Mg—Zr合金组织与性能的影响 总被引:4,自引:0,他引:4
研究了Sc对Al-Li-Cu-Mg-Zr合金的显微组织与拉伸性能的影响,结果表明,δ'(Al3Li)和S'(Al2CuMg)仍为含Sc合金中的主要强化相,Sc细化了合金的晶粒,降低了δ'颗粒的长大速度。促进了S'相的析出和均匀弥散分布,还使合金析出Al3Sc颗粒和Al3Li/Al3Sc复合析出相颗粒,这两种颗粒都有益于合金的性能,因此,加入Sc后合金表现出良好的强塑性配合。 相似文献
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1.IntroductionIntermetallicc0mp0undNi3Alhasthespecificpropertythattheyieldstrengthim-proveswiththeincrease0ftemperature.Thefundamentalresearchonhigh-temperaturestructuralmaterialshaJsmademuchprogress,andther0omtemperaturetensilepr0pertiesofNisAlalloysareimproveddramaticallywiththeaddition0falittleB[1'2].Beingasurfaceactiveelement,Cecanpurifyandmodifysteels,andimprovetheirductility,t0ughness,oxidationresistanceandc0rrosionresistance[3].Theeffect0fCe0nthefabricabilityandroomtemperaturetensil… 相似文献
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Wang GuotianDing HongshengChen RuirunGuo JingjieFu Hengzhi 《金属学报》2017,(11):1461-1468
Due to their excellent high-temperature strength, and good oxidation resistance, Ni(3)Albased alloys have long attracted considerable interest as a class of high-temperature structural material. These properties, combined with their unique high thermal conductivity, make them ideal for special applications, such as blades in gas turbines and jet engines. However, polycrystalline Ni3Al alloys show almost no ductility and extremely low fracture resistance at ambient temperatures. Ni3Al alloys with the high ductility at room-temperature can be adjusted by the microstructure through directional solidification (DS) and matching. It has been shown that the electric field can refine the solidification structure, reduce the dendrite spacing, promote the diffusion and change the solute redistribution in the solidification process. In order to improve the room temperature ductility of Ni3Al alloy, the effect of current intensity on microstructure of DS Ni-25Al alloy is investigated. In this work, the effects of constant current intensity and NiAl phase on the microstructure are researched. The results show that in the DC electric field, as the result of the aggregation of current along dendrite tip and the Joule heat at the tip of dendrite, the primary dendritic spacing (lambda) decreases with the increasing of current intensity. And the solid-liquid interface tends to be straight resulting from the Joule heat and Peltier effect caused by the segregation of current and the difference in conductivity between solid and liquid interface. When no direct current is applied the DS samples contain the L12 structure of Ni3Al matrix and B2 structure of NiAl precipitate phase. The microstructure is a duplex structure which consist of gray Ni3Al matrix and black NiAl precipitates. NiAl precipitates with regular shape and has obvious orientation along with the growth direction. When the DC current is applied, NiAl precipitates is irregular and dispersion and has no obvious directionality, due to Joule heat effect generated by the current effect, the undercooling increased and the precipitated NiAl phase transformed into thin martensite NiAl phase with twin crystal symmetry from the NiAl-B2 type structure. 相似文献
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Aluminum alloys containing lithium exhibit high strength, high elastic modulus, and low density. These alloys contain a metastable, coherent δ′ (Al3Li) phase which forms by homogeneous decomposition of the solid solution. Efforts are made to improve the ductility by alloying and heat treatment. In this work the corrosion behavior of AlLi, AlLiMn, AlLiZr, AlLiMg, and AlLiCu alloys was investigated as a function of composition and aging and correlated with the microstructure. The tests were made in a 3.5% NaCl solution, and included potential, potentiodynamic and potentiostatic measurements, and weight loss determinations. The results show that aging to peak hardness had little effect on the corrosion resistance. Overaging of the AlLi, AlLiMn, and AlLiZr alloys generally increased the susceptibility to corrosion, which has been attributed to the formation of the stable (AlLi) phase. Mg-containing alloys showed less severe effect of overaging because of the formation of the Al3MgLi phase which tied up some of the lithium. In the Cu-containing alloy the supersaturation with lithium was low and overaging did not affect the corrosion resistance. 相似文献
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G. Rosas R. Esparza A. Bedolla-Jacuinde R. Pérez 《Journal of Materials Engineering and Performance》2009,18(1):57-61
This work analyzes the effect of very small additions of Li and Ni on the mechanical properties of the Fe72Al28 intermetallic alloy, close to the Fe3Al ratio. Hardness and tensile strength at room temperature were analyzed for the cast Fe3Al intermetallic alloys as a function of Li and Ni additions. For this purpose, high-purity raw materials were melted in an
open induction furnace into a SiC crucible and the liquid alloys were poured into sand moulds to directly get tensile test-shaped
specimens to minimize machining. Mechanical tests were carried out in the as-cast condition as well as after a homogenization
heat treatment at 400 °C for 120 h. The obtained microstructure was characterized by XRD and SEM. Results show an increase
in ductility, particularly when Li was added. 相似文献
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EFFECTSOFCuandMgONMICROSTRUCTUREANDPROPERTIESOF-Al(3-4Wt%)LiALLOYSC.G.Jiao;G.F.YuandM.G.Yan(InstituteofAeronauticalMaterials,... 相似文献
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SURFACE REACTION OF Ni_3Al WITH WATER VAPOR OR OXYGEN 总被引:1,自引:0,他引:1
1.IntroductionManyresearcheshavedem0nstratedthatthebrittlefractureandpoorductilityatambienttemperature0fsomeintermetallicc0mp0undsarecausedbytheatmosphereofen.ir0n.entIl-4].Forexample,theel0ngationofFe3Alanditsalloystestedinairwasmuchlowerthanthatinvacuum0roxygenl516].Ni3Al-basedall0yswith0utbor0nandwitha1owcontent0fboronweresh0wnt0bequiteductilewithel0ngati0nof15-25%wl1entestedinvacuum0rpllreoxygen,whi1etheyexhibitedp0orductilityof4-10%inai,[7'8].Thisphenomen0nisbelievedtobeahydrogenembritt… 相似文献
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EFFECT OF Zr ON DUCTILITY OF CAST Ni_3 Al-BASE ALLOYS 总被引:1,自引:0,他引:1
ZHENG Zhi WU Weiwen GUO Jianting ZHU Yaoxiao Institute of Metal Research Academia Sinica Shenyang China Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(6):409-413
Many compressive and tensile tests showed that the room temperature ductility of boron-freeNi_3Al alloy may be markedly improved by a moderate addition of Zr.The ductility of thestoichiometric Ni_3Al and even slightly enriched with Al,may be improved fairly between 400—600℃,which behaves much better if Zr is added together with B.However,the high tem-perature ductility of Ni_3Al alloys containing Cr may be significantly increased by Zr whichsegregates slightly along grain boundaries.Thus,the toughening mechanism of Zr alloyingseems to be different from that of B addition. 相似文献
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D.G. Ren Z.Q. Li X.S. Fan J. T. Guo Laboratory of Atomic Imaging of Solids Institute of Metal Research The Chinese Academy of Sciences Shenyang China 《金属学报(英文版)》2000,13(4):1001-1011
1. IntroductionPolycrystalline Ni3AI materials, an intermetallic compound with the L12 ordered structure, have been studied extensively in the past few years becallse of their potential application at high temperature structural applications. The brittle intergranular fractures andthe dramatic ductilizing effect of small amounts boron in polycrystalline Ni3AI led on tostudy the structure and chemistry of grain boundary[1--3]. The intergranular fragility ofNisAI alloys has been explained by… 相似文献
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《Acta Materialia》2007,55(14):4845-4852
A first-principles method is employed to investigate the segregation behaviors of hydrogen and boron in Ni-based and Ni3Al-based alloys using two models. Chemical binding energy analysis shows that both boron and hydrogen are able to segregate to the interstices in the Ni phase, Ni3Al phase and Ni/Ni3Al interface. Boron, however, is bound to its neighbor atoms more tightly than hydrogen in both models and its stable state exists over a broader lattice misfit range compared with hydrogen. The bond order analysis we have proposed reveals the origin of the boron-induced ductility and hydrogen-induced embrittlment at the Ni/Ni3Al interface with different lattice misfit. The calculations indicate that hydrogen causes more severe embrittlement at the Ni/Ni3Al interface in Ni3Al-based than in Ni-based alloys. Furthermore, it is found that the boron-induced ductility and hydrogen-induced embrittlement are changed, and thus controllable, by the lattice misfit. Our results provide a quantitative explanation of many experimental phenomena caused by the addition of boron and hydrogen to Ni-based and Ni3Al-based alloys. 相似文献