The high-strength plate alloy 2324 is a modification of 2024 alloy composition and process conditions to increase strength in both plate and extrusions without a loss in fracture toughness and other characteristics. This datasheet provides information on key alloy metallurgy, as well as the effects of processing on mechanical properties of this 2xxx series alloy. A comparison of fracture toughness of 2324-T39 to 2024-T351 is presented.

Alloy 2198 is an Al-Cu-Li alloy that is used in combination with 2196-T8 stringers for the fuselage skins of the Bombardier C-Series. This datasheet provides information on composition limits of the alloy 2198 and provides a performance comparison of 2198-T8 and 2024-T351 alloys.

Alloy 2196 is a higher Li-containing alloy registered in 2000 for various aircraft extrusion parts. This datasheet provides information on composition limits and applications of alloy 2196 and 2296 as well as processing effects on mechanical properties of 2196-T8511 extrusions. A performance comparison of 2196-T8511 extrusion with alloy 2024 is also presented.

Heat treatment of aluminum alloys is assessed by various quality-assurance methods that include metallographic examination, hardness measurements, mechanical property tests, corrosion-resistance tests, and electrical conductivity testing. The use of hardness measurements in the quality assurance of heat treated aluminum products is effectively used in conjunction with the measurement of surface electrical conductivity. This article provides a detailed discussion of the error sources in eddy-current conductivity measurements. It also presents useful information on the variation of electrical conductivity of alloy 2024 samples as a function of aging time at different isothermal holding temperatures.

This article briefly describes the basic attributes of chromate conversion coatings and the processes for applying them. It provides information on the influence of substrate microstructure on the performance of coating deposits and on the mechanism of substrate protection supplied by chromate coatings. The article also discusses the development of replacement technologies in response to environmental constraints that have developed around the use of chromium-base compounds.

The extrusion and sheet alloy 6056 was developed to provide weldable thin extrusions with an excellent balance between high strength and corrosion resistance. This datasheet provides information on composition limits, processing effects on mechanical properties, and applications of this 6xxx series alloy. It provides a material performance comparison of aluminum alloys 6056-T6511 with 2024-T3511 and 6056-T8511 with 2024-T3511.

Corrosion, fatigue, and their synergistic interactions are among the principal causes of damage to aircraft structures. This article describes aircraft corrosion fatigue assessment in the context of different approaches used to manage aircraft structural integrity, schedule aircraft inspection intervals, and perform repair and maintenance of aircraft in service. It illustrates the types of corrosive attack observed in aircraft structures, including uniform, galvanic, pitting, filiform, fretting, intergranular, exfoliation corrosion, and stress-corrosion cracking. The article discusses geometric parameters such as pit dimensions, surface roughness, loss of metal thickness, and volume increase due to pillowing to quantitatively characterize the types of corrosion. It also explains the two most common fatigue life assessment methods used in the military aerospace industry: fatigue crack initiation and crack growth analysis.

Aluminum-lithium alloys have been developed primarily to reduce the weight of aircraft and aerospace structures. This article commences with a discussion on the physical metallurgy and development of aluminum-lithium alloys. It focuses on major commercial aluminum-lithium alloys, including alloy 2090, alloy 2091, alloy 8090, alloy CP276, and Weldalite 049. The article also lists the chemical compositions, physical properties, fabrication characteristics, corrosion performance, and general applications of these alloys. A comparison of alloy properties is represented graphically.

This article focuses on the three basic groups of flexible-die forming methods: rubber pad, fluid cell, and fluid forming. It provides information on the Guerin process, the Verson-Wheelon process, the trapped-rubber process, the Marform process, the Hydroform process, the SAAB process, and the Demarest process. The article provides a discussion on the procedures of these processes, as well as the presses and tools used. It describes the methods of hydraulic forming of thin metal parts, namely, hydraulic forming with diaphragm, hydraulic forming with gasket and pressure control, and hydrobuckling.

This datasheet provides information on key alloy metallurgy, mill product specifications, processing effects on physical and mechanical properties, and applications of high-strength aerospace alloys 2024 and Alclad 2024. It contains tables that list values of tensile property limits for 2024 sheet, plate, and round product forms. Figures illustrate the effect of stretching and aging on toughness of the 2024 sheet and the effect of temperature on tensile properties of 1.0 mm thick Alclad 2024-T3 sheet.

Dealloying is a corrosion process in which one or more elements are selectively dissolved, leaving behind a porous residue of the remaining elements. This article describes the dealloying in various systems, namely, dezincification, graphitic corrosion, dealuminification, and noble metal alloys dealloying. The current-potential behavior of a binary alloy undergoing selective dissolution is reviewed. The article highlights the four mechanisms required for the formation of porous metals: ionization-redeposition, surface diffusion, volume diffusion, and percolation model of selective dissolution.

This article focuses on the effects of mechanical plasticity on workability; that is, process control of localized stress and strain conditions to enhance workability. It describes the nature of local stress and strain states in bulk forming processes, leading to a classification scheme, including testing procedures and specific process measurements, that facilitate the application of workability concepts. Using examples, the article applies these concepts to forging, rolling, and extrusion processes. The stress and strain environments described in the article suggest that a workability test should be capable of subjecting the material to a variety of surface strain combinations. By providing insights on fracture criteria, these tests can be used as tools for troubleshooting fracture problems in existing processes, as well as in the process development for new product designs.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of wrought aluminum alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the corrosion-fatigue fracture, fatigue striations, tension-overload fracture surface, ductile fracture, cone-shaped fracture surface, intergranular crack propagation, transgranular crack propagation, stress-corrosion cracking, hydrogen damage, and grain-boundary separation of these alloys. Fractographs are also provided for a forged aircraft main-landing gear wheel and actuator beam, an aircraft wing spar, a fractured aircraft propeller blade, shot peened fillet, an aircraft lower-bulkhead cap, and clevis-attachment lugs.

Aluminum and its alloys are among the more formable materials of commonly fabricated metals. This article discusses the formability, bendability, and springback of aluminum and its alloys. It describes the forming limit diagrams that illustrate the biaxial combinations of strain that can occur without splitting. The article reviews various bending methods, such as draw, compression, ram and press, roll, and stretch or tension bending. It describes the process variations of incremental sheet forming (ISF), such as single-point incremental forming, two-point incremental forming, and kinematic incremental sheet forming. The article concludes with a discussion on spinning, warm forming, and superplastic forming.

This article discusses the general formability considerations of aluminum alloys. To conduct a complete analysis of a formed part, the required mechanical properties, as determined by several standard tests, must be considered. The article describes tension testing and other tests designed to simulate various production forming processes, including cup tests and bend tests, which help in determining these properties. It provides information on the equipment and tools, which are used in the forming of aluminum alloys. The article presents a list of lubricants that are most widely used in the forming. It also analyzes the various forming processes of aluminum alloys. The processes include blanking and piercing, bending, press-brake forming, contour roll forming, deep drawing, spinning, stretch forming, rubber-pad forming, warm forming, superplastic forming, explosive forming, electrohydraulic forming, electromagnetic forming, hydraulic forming, shot peening, and drop hammer forming.

This article discusses the effects of heavy metal impurities, environmental factors, the surface condition (such as as-cast, treated, and painted), and the assembly practice on the corrosion resistance of a magnesium or a magnesium alloy part. It provides information on stress-corrosion cracking and galvanic corrosion of magnesium alloys, as well as the surface protection of magnesium assemblies achieved by inorganic surface treatments.

The material data for forging can be divided into two categories, namely, mechanical properties and thermophysical properties. This article describes the flow characteristics of key engineering materials, such as steels, aluminum alloys, copper alloys, titanium alloys, and nickel-base superalloys. It discusses the thermophysical properties for designing or optimizing a metalworking process: specific heat, coefficient of thermal expansion, thermal conductivity/diffusivity, and density.

This article describes the types of closure mechanisms, including plasticity-induced, roughness-induced, oxide-induced, and fretting-debris-induced. It discusses test techniques used to establish a valid threshold value for aluminum alloy crack growth thresholds, steel crack growth thresholds, and titanium alloy crack growth thresholds. The near-threshold behavior of nickel-base superalloys is described. The article briefly reviews the threshold results for fiber-reinforced, whisker-reinforced, and particulate-re-inforced metal-matrix alloys. It explains the near-threshold fatigue crack propagation in welded joints and the fundamental considerations for modeling threshold behavior. The article concludes with a discussion on the effects of thresholds in the engineering design process.

This article discusses the concepts underlying linear elastic fracture mechanics and elastic-plastic fracture mechanics as well as their importance in characterizing the fracture behavior of the high-strength aluminum alloys. It describes the three methods used for analyzing elastic-plastic fracture, namely R-curve concept, J-integral concept, and crack tip opening displacement method. The article considers the primary measures used to assess the toughness of aluminum alloy castings and wrought alloys: notch toughness, tear resistance, and plane-strain fracture toughness.

The family of type 357 alloys contain the highest magnesium levels and are used where high strength is required. This datasheet provides information on key alloy metallurgy, fabrication characteristics, processing effects on physical and mechanical properties, and applications characteristics of Al-Si-Mg high-strength casting alloys.