Aluminum alloy 6013 sheet for new U.S. Navy aircraft

The recently developed aluminum alloy 6013-T6 has been selected for the fuselage skin and other applications on the U.S. Navy’s P-7A airplane, in place of the traditional 2024-T3 clad sheet. Alloy 6013-T6 is naturally corrosion resistant, like the well-established alloy 6061, and hence is used unclad. Its fatigue strength, fatigue crack growth and fracture toughness compare favorably with 2024-T3. Replacement of alloy 2024 with alloy 6013 also reduces manufacturing costs for formed parts, because 6013 is readily formed in the T4 temper, then simply aged to T6, thus avoiding the costly heat treatments and straightening required for alloy 2024.     

The U. S. Navy Titanium Program

Preliminary research to develop suitable alloys and the direction of future work is discussed.     

Mechanical and propulsion systems prognostics: U.S. Navy strategy and demonstration

Under the auspices of the Defense Advanced Research Projects Agency Prognosis Seedling Effort, a U.S. Navy strategy has been generated to develop, integrate, and demonstrate diagnostics, prognostics, health monitoring, and life management for propulsion and mechanical systems. This article presents the evolution of this overall strategy and its current status. The SH-60 program was initiated as the first proof-of-concept effort to develop, demonstrate, and integrate available and advanced mechanical diagnostic technologies for propulsion and power-drive system monitoring. Included in these technologies were various rule- and model-based analysis techniques to demonstrate and validate diagnostic and trending capabilities. Recently, there has been increased emphasis on prognostic capabilities, which provide early detection of the precursor and/or incipient fault condition to a component or sub-element failure condition, and can manage and predict the progression of this fault condition to component failure. This approach increases safety and significantly reduces supportability costs over the aircraft life cycle. Editor’s Note: Presentation of this paper is supported by the Air Force Research Laboratory, under agreement number F33615-01-D-5801. The U.S. Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Air Force Research Laboratory or the U.S. Government. For more information, contact William Hardman, Naval Air Warfare Center Aircraft Division, Propulsion & Power Department, Building 106, Unit 4, 22195 Elmer Road, Patuxent River, MD 20670-1534; (301) 757-0508; e-mail william.hardman@navy.mil.     

钛合金特点及其在美国海军中的应用

介绍了钛合金的特点,及美国在舰船上使用钛合金的部件、优越性和合金种类。     

铝锂合金的合金化与微观组织演化

评述了铝锂合金的发展历程和应用以及我国铝锂合金研究所取得的成果。阐述了第3代铝锂合金的成分、微观组织和性能特点,讨论了合金化元素在调控铝锂合金微观组织进而改善性能方面的作用。大量研究表明,这些合金化元素可改变铝锂合金中原有析出相的大小、形状、分布,或刺激新强化相的析出,也可以细化晶粒、控制再结晶和晶粒取向。时效析出过程的本质和动力学在很大程度上取决于合金化元素之间的交互作用和合金原子的团簇化过程。     

The potential for the SCC of titanium alloys under repository-relevant environments for U.S. nuclear waste

Stress corrosion cracking (SCC) is one of the most common corrosion-related causes of premature failure of metal structural components. This paper presents an assessment of the performance of titanium alloys (titanium grade 7 for the drip shield and grade 29 for the structural support), which may be subjected to SCC under proposed U.S. nuclear waste repository environments. The threshold stresses for SCC initiation, SCC crack propagation rates, and the threshold stress intensity factors for titanium grades 7, 28, and 29 are discussed.     

Stainless and acid-resisting steels and alloys

Conclusions Highly alloyed steels and alloys are produced in conformity with GOST or technical specifications in thick and thin sheets, beams and channels, bars, hot-rolled and cold-rolled pipe, and rod. Castings are produced in the specialized plant of the Ministry of Chemical and Petroleum Machine Building.The technology of welding stainless steels and alloys is given in [15] and [16].TsNIIChERMET. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 43–50, October, 1967.     

A nickel-based brazing alloy for brazing creep-resisting alloys and steels

The main types of brazing alloys used for brazing creep-resisting alloys and steels are investigated and their characteristics and main special features described. The aspects of the selection of brazing alloys for brazing different materials depending on the brazing conditions and the operating conditions of the components are discussed. Examples of the application of the technology of high-temperature brazing in the manufacture of aviation technology components are presented.     

A potentiokinetic reactivation method for predicting the I.C.C. and I.G.S.C.C. sensitivity of stainless steels and alloys

The present paper is a continuation of an earlier study dealing with a new method of electrochemical determination of the sensitivity to intercrystalline corrosion of stainless steel, based on reactivation from the passive state. This suggested test method was verified on austenitic chromenickel steels with increased carbon content and cold deformation. The ratio of charge during reactivation to that in the active region of the polarization curve (at increasing potential), expressed as a percentage, appears to give the optimum quantitative criterion of the tendency of steels to intercrystalline corrosion or intergranular stress corrosion cracking. The sensitivity of the method can be adjusted for the individual types of steels and alloys by changing the experimental conditions.