R.Noel
,
D. Furrer
,
G. Shen and J. Lemsky(Ladish Co.
,
Inc.
,
P.O. Box 8902
,
Cudahy
,
WI 53110-8902
,
USA Manuscript received 26 Augnst 1996)
金属学报(英文版)
Optimum properties of high temperature superalloys are derived from interactions of the composition,thermomechanical deformation, and heat treatment.Nickel-base alloys contain a variety of alloying elements in a large number of combinations to produce various desired effects. The general characteristics of any specific nickelbase superalloy is determined by composition.The control of the microstructure in wrought processed superalloys can further influence the resultant component properties.The relationship between microstructure and properties is key in advanced design and manufacture of turbine engine components, and requires extensive alloy and process characterization to achieve desired results.Various forging methods have been developed and employed throughout the years to process superalloy components.Hammer forging, Press forging,and advanced isothermal press forging equipment and processes have been designed and manufactured to process speciality metals which often have very narrow processing windows.Combination processes have also been introduced into turbine engine applications,which result in a hybrid of resultant structures and properties.One such speciality,combination process is the Ladish Iso Con process which utilizes isothermal forging and conventional forging to achieve unique properties not matched by any other single process.Ladish utilizes forging presses for conventional forging, hot-die forging and for isothermal forging, in addition to hammers and ring rolling mills for wrought processing.This wide range of equipment allows flexibility in process design and optimization.Variations in temperature, strain and strain rate have been shown to significantly influence resultant grain sizes and microstructures.Tools are being developed to allow forging processes and specific forging parameters to be evaluated and optimized with regard to final microstructure before shop triale are required. Sophisticated finite element method (FEM) models are allowing the design of forging processes on computers rather than by iterative trial and error methods.
关键词:
:forging
,
null
,
null
T. Carneiro
,
J. Radavich
,
D. Furrer
金属学报(英文版)
The role of niobium in nickel-based superalloys is reviewed. The importance of niobium as a strengthener is discussed. New developments in nickel-based superalloys are also briefly mentioned, including some results that show improved resistance to sulfidation by niobium. Research results from a current program on the role of niobium in the Russian powder metallurgy alloy EP741NP are presented. Future research plans on the role of niobium in superalloys are also discussed.
关键词:
niobium
,
null
,
null
Physics and Chemistry of Liquids
In earlier work, Ma [S.K. MA, Phys. Rev. Lett., 29, 1311 (1972)] has studied the critical exponents and for charged and neutral Bose gases. Here we use the result of Ma, valid for general dimensionality d but only to O(m-1), where m is the number of components of the Bose field, to write a relation between (d) and (d) to O(m-1). This then motivates, but now for the Ising model, a relationship between the critical exponents and , via the dimensionality d. We finally demonstrate a connection between the two renormalisation group eigenvalues yt and yh, via the critical exponent with a dimensional dependence.
关键词:
critical exponents;Ising model;dimensionality
赵国华
,
齐砚勇
,
潘玉峰
硅酸盐通报
对YNLL水泥厂2500 t/d生产线进行热工标定并分析,系统烧成热耗为3889 kJ/kg.cl,高于全国平均水平.高温风机拉风偏大,一级筒出口温度为370℃,偏高.篦式冷却机效果欠佳,AQC抽风量偏高,直接影响了熟料质量和余热发电量,热回收效率偏低.经过改进和优化,熟料产能提高为2600 t/d.该生产线系统还有比较大的潜力,熟料产量还有可能进一步提高,热耗及电耗均可能明显下降.
关键词:
热工标定
,
新型干法水泥
,
篦冷机
曹华夏
,
毕金栋
,
李昌勇
硅酸盐通报
对LNZL水泥厂2500 t/d生产线进行热工标定并分析,该厂熟料产量超过设计产量28.96％,达到3224.1t/d.系统烧成热耗为3302.6kJ/kg熟料,低于全国平均水平,一级筒出口温度为334℃,稍有些偏高;系统的分离效率为91.49％,出预热器飞灰量偏高,还有明显的改善空间.篦式冷却机效果欠佳,直接影响了熟料质量和余热发电量,热回收效率也偏低.该生产线系统还有比较大的潜力,如经过改进和优化,熟料产能还有可能进一步提高,热耗及电耗均可明显下降.
关键词:
热工检测
,
水泥生产线
,
运行情况
Physical Review B
In the investigation of the optical and magnetic properties of the semiconductors containing transition-metal ions, the one-electron orbital cannot be treated with a pure d orbital because of a strong covalence. This paper presents the energy matrix of the d*(8) and d*(2) (d* means a modified d function) system, in which the covalence is described by two covalent factors. The differences between the matrix diagonal elements of the t(2)(m)e(n) term of the d*(8) system and the t(2)(6-m)e(4-n) term of the d*(2) system vary with m and n. The d(N) electron system can be explained with the d(10-N) hole system because the difference between the energy matrix of the d(N) and d(10-N) systems has a fixed value. However, this kind of simple relation does not exist for the d*(N) and d*(10-N) systems when the covalence is considered. A numerical calculation shows that the variation of the energy levels with the covalence for Ni2+ in the d*(8) electron system is larger than that in the d*(2) hole system. The calculated energy levels obtained from the d*(8) matrix are in good agreement with the experimental data of the Ni2+ ion for ZnS:Ni and ZnSe:Ni. This suggests that the d*(8) electron system instead of the d*(2) hole system should be used in the investigation of optical and magnetic properties of semiconductor containing Ni2+ ions.
关键词:
zns-ni;absorption;vanadium;impurities;spectra;ions
Materials Chemistry and Physics
In this study, the phytic acid conversion coating, a new environmentally friendly chemical protective coating for magnesium alloys, was prepared. The influences of phytic acid concentration on the formation process, microstructure, chemical state and corrosion resistance of the conversion coatings on AZ91 D magnesium alloy were investigated by means of weight gain measurement, field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS), respectively. And the depth profile of all elements in the optimal conversion coatings was analyzed by auger electron spectroscopy (AES). The results show that the growth, microstructure, chemical state and corrosion resistance of the conversion coatings are all obviously affected by the phytic acid concentration. The concentration of 5gl(-1) corresponds to the maximum weight gain. The main elements of the coating are Mg, Al, O, P, and C, which are distributed gradually in depth. The functional groups of conversion coatings formed in higher concentration phytic acid solution are closer to the constituent of phytic acid than those formed in lower concentration phytic acid solution. The coatings formed in 1-5 gl(-1) are integrated and uniform. However, those formed in 20-50 gl(-1) have some micro-cracks on the (x phase. The coating formed in 5 gl(-1) has the best corrosion resistance, whose open circuit current density decreases about six orders than that of the untreated sample, although the coatings deposited in 1-20 gl(-1) can all improve the corrosion resistance of AZ91 D. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
关键词:
concentration;magnesium alloys;phytic acid;conversion coatings;corrosion-resistance;chromatography;behavior;copper;mg
张兴
,
郑成武
,
李宁
,
周兴丹
,
李正强
,
华瑞茂
液晶与显示
doi:10.3788/YJYXS20122704.0448
介绍了3D显示的基本原理,重点介绍了目前3D显示的主流技术类型,包含了眼镜式3D技术以及裸眼式3D技术,其中眼镜式3D技术包含色差式3D技术、偏光式3D技术和主动快门式3D技术;裸眼式3D技术包含视差屏障式3D技术、柱状透镜式3D技术、指向光源式3D技术和多层显示式3D技术.阐述了各种3D显示技术的基本实现原理和应用领域、并对涉及液晶显示的几种3D技术的优缺点进行了对比.结合液晶材料的特点与3D液晶显示的实际要求,阐述了3D液晶面板对液晶材料快速响应方面的要求,以及液晶透镜对液晶材料光学各向异性参数的要求.
关键词:
3D显示
,
眼镜式3D显示
,
裸眼式3D显示
,
液晶材料
D.Han
,
S.R.Qiao
,
M.Li
,
J.T.Hou
,
X.J.Wu
金属学报(英文版)
The differences of tension-tension fatigue and tensile creep characters of 2D-C/SiC and 3D-C/SiC composites have been scrutinized to meet the engineering needs. Experiments of tension-tension fatigue and tensile creep are carried out under vacuum high temperature condition. All of the high temperature fatigue curves are flat; the fatigue curves of the 2D-C/SiC are flatter and even parallel to the horizontal axis. While the tension-tension fatigue limit of the 3D-C/SiC is higher than that of the 2D-C/SiC, the fiber pullout length of the fatigue fracture surface of the 3D-C/SiC is longer than that of the 2D-C/SiC, and fracture morphology of the 3D-C/SiC is rougher, and pullout length of the fiber tows is longer. At the same time the 3D-C/SiC has higher tensile creep resistance. The tensile curve and the tensile creep curve of both materials consist of a series of flat step. These phenomena can be explained by the non-continuity of the damage.
关键词:
2D-C/SiC
,
null
,
null
