材料期刊网

Structural Applications of NiAl

R.Darolia(GE Aircraft Engines , 1 Neumann Way , Cincinnati , OH 45215 , USA)

材料科学技术（英文）

Alloys based on NiAl offer significant payoffs as structural materials in gas turbine applications due to a unique range of physical and mechanical properties These properties include high melting temperature. low density. high thermal conductivity. and excellent environmental resistance Very significant improvements in the strength and ductility of NiAl single crystals have been achieved through alloying. Tensile strength and stress rupture properties which compete with current Ni-base Superalloys have been achieved through precipitation of an ordered L21 Heusler phase in NiAl single crystals Room temperature tensile ductility as high as 6% has been produced in NiAl single crystals containing less than 0.5% (atomic) of Fe. Ga or Mo. However. a single alloy with both room temperature ductility and sufficient high temperature strength has not yet been developed. While activity to develop on alloy with both high temperature strength and room temperature ductility continues. the Current approach also emphasizes design and test methodologies which can accept a material with limited ductility and damage tolerance More work is required on measuring and understanding strain rate sensitivity and impact behaviour While several significant challenges still remain. excellent progress has been made in many areas, and the prognosis for using NiAl alloys as high temperature structural materials is promising

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THE EVOLUTION OF TECHNOLOGY DEVELOPMENT AT GE CORPORATE R & D

T.B.Cox(GE Corporate Research & Development , Niskayuna , NY 12309 , USA Manuscript received 26 August 1996)

金属学报(英文版)

A brief review of the nearly 100 year history of Corporate Researeh and Development at GE is presented. Observations on the changing nature and relevance of industrial research are discussed. Examples of current technology projects for aircraft engine materials are reviewed. Emphasis of these projects is placed on high performance,low cost and high quality.

关键词: :spray forming , null , null

NICKEL-BASED ALLOYS IN GE AIRCRAFT TURBINES: PAST, PRESENT & FUTURE

D. Chang , R. Schafrik

金属学报(英文版)

Improvements in materials have been critical to advances in the propulsion system. Over the past 50 years, many improvements have been made to nickel-based superalloys to satisfy design requirements; several key developments will be highlighted. Today, millions of pounds of superalloys are annually produced for use in turbine blades, vanes, disks, cases, and frames throughout the engine. Looking to the future, several themes emerge, although predicting the future is inherently risky.

关键词: jet engine , null

NICKEL-BASED ALLOYS IN GE AIRCRAFT TURBINES:PAST,PRESENT & FUTURE

金属学报(英文版)

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R & D ACTIVITIES ON AEROSPACE MATERIALS IN KOREA

H.M. Kim(Korea Institute of Machinery and Materials , Korea Manuscript received 26 August 1996)

金属学报(英文版)

This paper briefly reviews research and development programs in Korean aerospace industry,with an emphasis on aircraft materials technology. International collaborations in these areas are outlined and the R & D activities are highlighted against the　background of the national economy.It is shown that the investment from government agencies and large enterprises has led to healthy development of aerospace materials industries in Korea.

关键词: :R & D , null , null , null

Ge掺杂碳化硅晶体的生长缺陷

张福生 , 陈秀芳 , 崔潆心 , 肖龙飞 , 谢雪健 , 徐现刚 , 胡小波

无机材料学报 doi:10.15541/jim20160129

采用物理气相传输法(PVT)制备了2英寸Ge掺杂和非掺SiC晶体,并使用二次离子质谱仪(SIMS)、显微拉曼光谱(Raman spectra)仪、体式显微镜、激光共聚焦显微镜(LEXT)和高分辨X射线衍射(HRXRD)仪等测试手段对其进行了表征.结果表明,Ge元素可以有效地掺入SiC晶体材料中,且掺杂浓度达到2.52×1018/cm3,伴随生长过程中Ge组份的消耗和泄漏,掺杂浓度逐渐降低;生长初期高浓度Ge掺杂会促使6H-SiC向15R-SiC晶型转化,并随着生长过程中Ge浓度的降低快速地转回6H-SiC稳定生长.用LEXT显微镜观察发现,生长初期过高的Ge掺杂导致空洞明显增多,位错密度增加,掺杂晶体中位错密度较非掺晶体增大一倍.HRXRD分析表明掺Ge能增大SiC晶格常数,这将有利于提高与外延Ⅲ族氮化物材料适配度,并改善器件的性能.

关键词: 物理气相传输法 , Ge掺杂 , SiC晶体 , 晶格常数

LIQUIDUS OF SYSTEM Ag-Cu-Ge

LIU Shuqi , YI Tao , Peking University , Beijing , China

金属学报(英文版)

The diagram of Ag-Cu-Ge system was constructed from the investigation of 13 internal sec- tions by DTA heating as well as cooling curves in an atomsphere of dry N_2 . The phase dia- gram is subdivided into two pseudo-ternary systems shown as Ag-Cu-Cu_3Ge and Ag-Cu_3Ge-Ge. Both systems belong to simple eutectic type. The ternary eutectic points lie in." E_1, Ag(22.0)-Cu(58.8)-Ge(19.2), 632℃ and E_2 , Ag(44.3)-Cu(29.5)-Ge(26.2), 533℃. The three side binary systems were redetermined.

关键词: phase diagram , null , null

Design of Polymer Coatings in Automotive Engines

材料保护

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Crystal structures of compounds in the pseudobinary system Gd5Ge4-La5Ge4

Journal of Alloys and Compounds

Crystal structures of compounds at ambient temperature in the pseudobinary system Gd5Ge4-La5Ge4 were studied by X-ray powder diffraction (XRD). There exist three single-phase regions in this system. The crystal structure of Gd5Ge4, La5Ge4 and Gd3La2Ge4, which are prototype compounds in three phase regions, respectively, were reported. The Gd5Ge4 and La5Ge4 crystallize in the orthorhombic Sm5Ge4-type structure with space group Pnma. The ternary intermediate compound Gd3La2Ge4, which is determined for the first time, crystallizes in the monoclinic Gd5Si2Ge2-type structure with space group P112(1)/a. The Rietveld powder diffraction profile fitting technique was used for the refinement of crystal structure. The lattice parameters, atomic occupations, interatomic distances of the Gd5Ge4, La5Ge4 and Gd3La2Ge4 compounds were derived. (C) 2003 Elsevier B.V. All rights reserved.

关键词: rare earth compounds;crystal structure;X-ray diffraction;phase-relationships;gd-5(si2ge2);transition;silicon

Ge₃₀Se₇₀硫系玻璃的特征温度和性能^*

贾婷婷 , 坚增运 , 许军锋 , 朱满 , 常芳娥

金属学报 doi:10.11900/0412.1961.2015.00501

通过熔融-淬冷的方法制备Ge₃₀Se₇₀硫系玻璃块状试样, 利用XRD判定所制试样的非晶态程度, 采用DSC热分析方法测定该试样的玻璃化转变温度T_g和起始析晶温度T_x, 通过VFT方程拟合法确定试样的动力学理想玻璃化转变温度T₀, 采取分段加热法分析Ge₃₀Se₇₀ 玻璃试样和同成分晶体试样在设定温度范围内的比热容. 通过计算出的比热容拟合出Ge₃₀Se₇₀玻璃和晶体的比热容方程, 即c_p,l=0.0002T+0.3337和c_p,c=0.00006T+0.4594. Ge₃₀Se₇₀试样的T_g和T₀分别为590和581 K, 且T_g随着升温速率R的增大而增加. 在低于玻璃转化温度前时, Ge₃₀Se₇₀玻璃试样的平均比热容约为11.8 J/(molK), 红外透过率约为60%, 红外性能良好. 获得Ge₃₀Se₇₀玻璃的约化转变温度T_rg介于0.5~0.667之间, 形核率极低, 表明Ge₃₀Se₇₀玻璃的成玻能力良好.

关键词: 硫系玻璃 , 分段加热法 , 玻璃转变温度 , 比热容