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LI Hui Institute of Metal Research Academia Sinica Shenyang ChinaLIU Xiang Northeast Institute of Technology Shenyang ChinaGUO Jianting HU Zhuangqi Institute of Metal Research Academia Sinica Shenyang China Associate Professor Institute of Metall Research Academia Sinica Shenyang China 《金属学报(英文版)》1989,2(4):256-261
By means of nonstoichiometry,rapid solidification and adequate boron addition,the tensilestrength and bending resistance of Ni_3Al has been improved.When adding 0.52 to 1.37 at.-%B into Ni_3Al,which has the beneficial effect on the ductility.If boron addition is too high,there are coarse Ni_(23)B_6 particles and NiB_(12) phases found at the grain boundaries.Boronmodification in Ni_3Al promotes the ordering in the region near grain boundaries.The grainboundary of boron free Ni_3Al is a large angle one,but turns into a small angle grain bound-ary with sub-grains of dislocation characteristics when the boron content in Ni_3Al reaches1.37 at.-%. 相似文献
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GUO Jianting LI Hui SUN Chao ZHU Yaoxiao Institute of Metal Research Academia Sinica Shenyang China GUO Jianting Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1990,3(3):170-176
The microstructure and the mechanical properties from room temperature up to 1050℃ ofNi_3Al alloys containing 0—0.6 at.-%Zr,0—7.7 at.-%Cr and 0—2.22 at.-%B have beenstudied.It was found that the temperature dependence of their yield strength variation revealsto be anomalous,i.e.the strength increases with the temperature raising,and then decreasestill it surpassed the peak value.Both Zr and Zr+Cr may improve the yield strength of the al-loys in the entire range of testing temperatures,as well as the tensile strength and elongationunder high temperatures.B is favourable to raise the tensile and yield strengths of the alloys,and also plasticity.But the strength will reduce as B added is over 2.22 at.-%.TheNi_(20)Al_3B_6 and Ni_3Al eutectic mixture like islands and globes precipitated inside the grainsand along the grain bounderies,which are harmful to the strength and ductility,may beformed when the B content exceeds the limit of solubility. 相似文献
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ZHOU Yizhang ZHANG Tianxiang ZHU Yaoxiao HU Zhuangqi SHI Changxu Institute of Metal research Academia Sinica Shenyang China Assistant Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(6):468-470
Investigation was made of the ductility and microstructure of a series of cast Ni_3Al-base al-loys,with 19—23 at.-% Al and other alloying elements.An obvious improvement onmorphology,distribution,amount and size of primary Ni_3Al(γ')intermetallic compound wasapproached by such alloying elements such as Hf,Ti and Zr,but no more by Nb,W and Ta.The formation of ductile γ'-γ-γ' boundaries in the alloys with refined primary γ'-phase caneliminate the weakened nature of brittle γ'-γ' boundaries,and reduce the size of primaryγ'-phase to tens of μm.Thus,the ductility of the alloys,especially at intermediate tempera-tures may be markedly improved.In addition,an alloy free from Cr is still significantlyductile,and only its structure is refined.The availability of Cr to improve the intermediatetemperature ductility seems to be due to the change of amount and distribution of γ-phase. 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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YANG Wenying LU Fanxiu ZHANG Shouhua University of Science Technology Beijing Beijing China Department of Materials Science Engineering University of Science Technology Beijing Beijing China 《金属学报(英文版)》1991,4(2):147-150
The “order-disorder” model was adopted to calculate the lattice vacancies related to the com- position change in Ni_3Al alloys.A great deal of vacancies,i.e.,the non-stoichiometric vacan- cies,may exist in the Ni_3Al alloys containing Al over stoichiometry,i.e.25 at.-%.This was confirmed by the positron annihilation technique.Therefore,the influence of Al content on the enhancing behaviour of B towards the ductility of Ni_3Al alloys can be understood by the interaction of non-stoiehiometric vacancies and B atoms. 相似文献
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WU Weitao ZHANG Jianqing ZENG Chaoliu NIU Yan SHEN Weiliang Corrosion Science Laboratory Institute of Corrosion Protection of Metals Academia Sinica Shenyang China Professor Institute of Corrosion Protection of Metals Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(7):11-15
Hot corrosion of intermetallic compound Ni_3Al-0.2B was studied by electrochemicaltechniques combined with physical analyses.It was found that hot corrosion resistanceof Ni_3Al-0.2B is rather inferior.Sulfidation-oxidation is responsible for the acceleratedcorrosion.The addition of 6at.-% Cr and 0.5at.-% Zr to Ni_3Al-0.2B may accelerateits corrosion. 相似文献
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本文应用电化学方法及物相分析技术研究了Ni_3Al-0.2B金属间化合物在熔融NaCl-(Na,K)_2SO_4中的腐蚀.发现Ni_3Al-0.2B耐熔盐热腐蚀能力极差,硫化-氧化是腐蚀破坏的主要原因.Ni_3Al-0.2B中添加6at.-%Cr,0.5at.-%Zr加速了材料的腐蚀。 相似文献
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WANG Shuhe GUO Jianting LI Hui SUN Chao TAN Minghui LAI Wanhui Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(3):183-187
An additive of Y to Ni_3Al based alloy may form a phase YNi_5 which increases in amount withthe increase of Y content.It was found that the YNi_5 phase in Ni_3Al alloy could remarkablymake its grains finer and its grain boundaries more crooked other than straight.If the Y con-tent≥0.1 wt-%,it occurs as solid solution state and is favorable to high temperaturecompressive properties and oxidation resistance of the alloy.While Y≥0.3 wt-%,the forma-tion of YNi_5 is predominant in the shape of irregular strips inside Ni_3Al grains and alongtheir grain boundaries.This seems to be quite harmful to high temperature strength,ductilityand oxidation resistance of the alloy. 相似文献
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通过SEM动态拉伸形变试验,研究了具有各种化学成分和不同热处理态Ni_3Al合金的形变滑移特征,并用TEM观察了晶界区域的位错组态。研究结果表明,在含硼Ni_3Al合金的晶界附近存在一个过渡滑移区,该区域中滑移线重新取向或其它滑移系开动,从而产生了局部应变调节并使晶界应力集中松弛。硼降低了开动晶界位错源所需的应力并可能同时增加了位错源本身的数目。硼对Ni_3Al的韧化作用强烈受到基体Al含量、合金元素及热处理等因素的影响。 相似文献
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The deformation behaviours of Ni_3Al alloys with various chemical compositions and subjectedto different heat treatments were in situ observed under SEM. Moreover,in situ observationsof slip trace were supplemented by the direct observation of dislocation arrangements underTEM.In B-doped Ni_3Al alloys it is shown that close to the grain boundary there exists a thinslip transition region,within which slip lines are reoriented or other slip systems are operatedto produce a local strain accommodation and to relax the stress concentration at grain bound-aries.Boron seems to lower the stress for dislocation generation from the grain boundaries orto ease the cross-slip close to the boundaries,and also to increase the number of dislocationsources.However,B-enhenced ductility is seriously affected by stoichiometry,the addition ofa tertiary alloy element and heat treatment,etc.. 相似文献
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ZHANG Jishan TANG Yajun ZHANG Jinghua ZHANG Zhiya YU Yang LI Ying ao HU Zhuangqi Institute of Metal Research Academia Sinica Shenyang China ZHANG Jishan Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1990,3(2):149-151
A Zr-rich phase,Ni_5Zr,with low melting point has been fouhd in an Ni_3Al alloy doped withZr(1.2at.-%).It will cause the incipient melt of the alloy after being homogenized at 1300℃.This makes it difficult to homogenize the coarse casting structures completely and limits thefurther improvement of properties of the Ni_3Al alloy. 相似文献
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LOCALCHEMISTRYANDTHECOHESIVESTRENGTHOFGRAINBOUNDARIESINNi_3AlShanthiSubramanian;DavidMuller;JohnSilcoxandStephenL.Sass(Depart?.. 相似文献
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Effect of minor Sc and Zr on microstructures and mechanical properties of Al-Zn-Mg based alloys 总被引:13,自引:1,他引:12
1 INTRODUCTIONAluminumalloycontainingminorScandZrisanew groupofstructurematerials ,whichhashighstrength ,highductility ,goodcorrosionresistanceandweldability[1~ 5] .Itismainlyappliedinaerospace ,nuclearenergyandshipsindustry .Thesi multaneousadditionofSc ,ZrorT… 相似文献
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Ni3Al晶界结构的计算机模拟 总被引:2,自引:0,他引:2
本文运用嵌入原子法势函数和静态弛豫最陡梯度的计算方法,模拟[100],[110]和[111]轴一系列具有不同晶界几何参量及化学成分的Ni_3Al对称倾侧晶界原子结构、晶界能和晶界的内聚能、电荷密度分布及应力场等内容,并着重研究和讨论了它们与硼偏聚,Ni_3Al的晶界韧脆行为,特别是硼韧化的化学计量效应之间的关系。 相似文献
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《Scripta materialia》2002,46(4):299-303
An improvement in the tensile ductility from the traditional 3–20% in 6.35-mm-thick molybdenum weldments has been achieved through the addition of Zr, Al, C and B at the ppm level. Atom probe tomography has revealed segregation of Zr, B and C to and depletion of O at the grain boundaries in the base metal and the heat affected zone. 相似文献