Diffusion bonding between nickel-base superalloy K24 and heat-resisting steel 1Cr11Ni2W2MoV

IntroductionSLlperalloyandheat-resistingsteelarenowwidelyusedasstructurematerialsinaerospace,a\-lationalldshipbuildingindustries.Nickel-basesuperalloywasfirstlyrevealedasanengineeringmaterialduringtheearly1960swhenitwasrecognizedasbeingsuitableforllledium-temperaturegasturbinel'l.Now.nickel-basesuperalloyhasbeenpracticallyusedinhigheffectiveturbinestosatisfytheincreasingdemandsforhighertemperatureenvironmentsIZI.Insomeaerospaceengines,theimpellersshouldserveattemperatureof1000C~1100C,andala…     

The nature of crystallites in solidified,rigid-chain,liquid crystal polymers

Two rigid chain thermotropic liquid crystal polyesters have been examined by X-ray diffraction and thermal analysis in order to explore the nature of the crystallites in the solid state. A comparison of quenched and slow-cooled specimens indicates the presence in the quenched material of microcrystals that are too small to give clear X-ray lines. It is proposed that this is due to the very low surface energy associated with the nematic chain morphology. Both the enthalpy and entropy of fusion are much lower than in conventional polymers and are related to the molecular design of the thermotropic polymers.     

Intermetallic phase formation in directionally solidified Al−Si−Fe alloy

The present study has been undertaken to better understand the solidification behavior of Al−Si−Fe alloys containing 7wt.% Si and 0.9wt.% Fe, with particular regard to the formation of phase during controlled solidification and influence of growth rates on intermetallic phase selection. The alloys studied were Al-7Si-0.9Fe alloys, which were produced by a modified Bridgman solidification arrangement. These alloys were solidified unidirectionally with different growth rates (1–30mm/min). The solidified microstructure of these alloys consists of the growth of primary aluminum and multiple second phase reactions.     

Oxidation behaviors of Ni-Cr-Al superalloy foams at 1 000 ℃ in air

The oxidation behaviors of Ni-16Cr-xAl （x=4.5%, 9.0%, mass fraction） superalloy foams in air at 1000℃ were investigated. The effects of AI content on the resistance to high temperature oxidation were examined. The oxidation mechanisms of the foams were discussed. The results show that the resistance to the oxidation of the Ni-16Cr-xA1 based alloy at 1 000 ℃ increases with the content of A1 increasing from 4.5% to 9.0%. Complex oxide products are formed on the surface of the superalloy foams after the oxidation. Cr203 and A1203 are the predominant oxides for the scales of the foams with 4.5% A1 and 9% A1, respectively. Excellent high temperature oxidation resistance and superior pore conformation stability for the Ni-16Cr-xA1 based superalloy foam with 9% A1 can be mainly attributed to the formation of relatively continuous and protective A1203 oxides on the surface of the foam.     

镍基高温合金粉末筛分工艺的研究

介绍了粉末筛分设备及其主要工艺参数 ,并围绕筛分处理的生产效率及粉末质量的影响因素展开了讨论     

Microstructure and Its Influence on Mechanical Behaviour of Directionally Solidified DZ38G Superalloy

The features of microstructure and theirinfluence on mechanical properties onstress-rupture as well as thermal fatigue ofdirectionally solidified DZ38G nickel-base su-peralloy have been investigated.It has beenfound that the contents of carbides on grainboundaries are increased and morphology of γ'-precipitates has been changed after testing.Particularly γ'-precipitates coalesced intoraft-like in morphology perpendicular to theapplied stress-axis have been observed thathas no detrimental effect on the stress-rupturebehaviour.The tendency of σ-formation hasalso been discussed.The σ-phase can be avoidedwhen the process parameters are chosenappropriately during solidification.     

爆炸复合钢板界面射流熔化与凝固的研究

本文研究了奥氏不锈钢／普通低合金风时复合钢板界面熔区的形成。通过试验发现,爆炸时钢板碰撞形成的射注被截断的位置与铸态凝固组绢存在的位置一致,说明界面熔区是由射流构成的。通过分析,射流熔化的原因并非仅仅来自绝热剪切,射流与基体的摩擦生热同样起着重要的作用。身流熔区的凝固组织对复合板质量影响较大;而凝固组织的质量与爆焊工艺有着密切关系。     

High Temperature Oxidation of FGH96 P/M Superalloy

High temperature oxidation behaviors of FGH96 P/M superalloy have been studied in air at temperatures ranging from 600 to 1000℃. By means of isothermal oxidation testing,X-ray diffraction,SEM(scanning electron microscopy),and EDS(energy dispersive X-ray spectroscopy) analyses,the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased,the oxidation rate,the scale thickness,and scale spallation increased. FGH96 P/M superalloy exhibits good oxidation resistance at temperature below 800℃. The oxidation kinetics follows an approximately parabolic rate law,and the oxide layer was mainly composed of Cr2O3,TiO2,and a little amount of NiCr2O4. The oxidation is controlled by the transmission of chromium,titanium,and oxygen through the oxide scale.     

快速凝固高强度高导电Cu-Cr合金的组织和性能

采用单辊快速凝固方法获得了Ｃｕ－０．８Ｃｒ微晶合金,对淬态及时效处理后合金的 导电性及显微硬度进行了系统研究。研究结果表明：快速凝固Ｃｕ－０．８Ｃｒ合金经适当的时效 处理,可以在保持高导电率的前提下,大幅度提高合金的硬度。在５００℃时效３０ｍｉｎ,导电率 为８２％ ＩＡＣＳ,显微硬度为HＶ１８５。