This datasheet provides information on key alloy metallurgy, processing effects on physical and mechanical properties, and applications of natural aging casting alloys 711.0 and 712.0. The fatigue strength of smooth and notched permanent mold aluminum casting of C712.0-F is illustrated.

Aging is a process where the structural and/or functional integrity of components will be continuously degraded by exposure to the environmental conditions under which they are operated. This article discusses aging mechanisms in various components of military systems such as structural parts, engines, and subsystems. It describes the aging management processes such as full-scale structural testing and practical life-enhancement methods. The article reviews control and prevention systems such as usage and health monitoring systems necessary to provide effective corrosion maintenance on military systems. Failure prediction techniques, namely, the equivalent pre-crack size approach, life-cycle cost modeling and simulation, and holistic life-prediction methodology are also discussed.

This article describes weathering and environmental factors that contribute to degradation in plastics, including temperature variations, moisture, sunlight, oxidation, microbiologic attack, and other environmental elements. It presents a general overview of aging factors, their effects on plastic materials, and the accelerated test methods that can be used to estimate the reaction of a plastic component during actual use. The article focuses on the determination of service temperature as it indicates the ability of a material to retain a certain property, when exposed to elevated temperatures for an extended period of time. It concludes by describing various degradation processes, namely, thermal degradation, thermal oxidative degradation, photooxidative degradation, environmental corrosion, and chemical corrosion and discussing the ways of detecting these degradation processes.

Accelerated life testing and aging methodologies are increasingly being used to generate engineering data for determining material property degradation and service life (or fitness for purpose) of plastic materials for hostile service conditions. This article presents an overview of accelerated life testing and aging of unreinforced and fiber-reinforced plastic materials for assessing long-term material properties and life expectancy in hostile service environments. It considers various environmental factors, such as temperature, humidity, pressure, weathering, liquid chemicals (i.e., alkalis and acids), ionizing radiation, and biological degradation, along with the combined effects of mechanical stress, temperature, and moisture (including environmental stress corrosion). The article also includes information on the use of accelerated testing for predicting material property degradation and long-term performance.

Engineering plastics, as a general class of materials, are prone to the development of internal stresses which arise during processing or during servicing when parts are exposed to environments that impose deformation and/or temperature extremes. Thermal stresses are largely a consequence of high coefficients of thermal expansion and low thermal diffusivities. Although time-consuming techniques can be used to analyze thermal stresses, several useful qualitative tests are described in this article. The classification of internal stresses in plastic parts is covered. The article describes the effects of low thermal diffusivity and high thermal expansion properties, and the variation of mechanical properties with temperature. It discusses the combined effects of thermal stresses and orientation that result from processing conditions. The article also describes the effect of aging on properties of plastics. It explains the use of high-modulus graphite fibers in amorphous polymers.

This article describes the processes involved in photochemical aging and weathering of polymeric materials. It explains how solar radiation, especially in the UV range, combines with atmospheric oxygen, driving photooxidation and the development of unstable photoproducts that cause various types of damage when they decompose, including the scission of carbon bonds and polymer chains. The article illustrates some of the degradation reactions that occur in different polymers and presents an overview of the strategies used to prevent such reactions or otherwise mitigate their effects.

Compared to cold-formed parts, age-formed parts have lower residual stresses and consequently better stress corrosion resistance. This article addresses the technical issues that arise in the investigations of creep in precipitate-strengthened materials. The issues addressed help in developing alloys and tempers particularly suited for the age-forming process. The different steps involved in the program for predicting the final part shape are discussed. These basic steps involve developing mechanical tests to study creep at low temperatures and low stresses, describing low-temperature creep in terms of a constitutive model, and then using the constitutive model in a process model or finite element analysis to predict the final part shape.

This article describes the effects of alloying and heat treatment on the metastable transition precipitates that occur in age hardenable aluminum alloys. Early precipitation stages are less well understood than later ones. This article details the aging sequence and characteristics of precipitates that occur in the natural aging and artificial aging of Al-Mg-Si-(Cu) alloys, Al-Mg-Cu alloys, microalloyed Al-Mg-Cu-(Ag, Si) alloys, aluminum-lithium-base alloys, and Al-Zn-Mg-(Cu) alloys. Crystal structure, composition, dimensions, and aging conditions of precipitates are detailed. Effects of reversion, duplex annealing, and retrogression and re-aging are included.

This article focuses on the aging characteristics of solution and precipitation heat treated aluminum alloy systems and their corresponding types. It includes information on aluminum-copper systems, aluminum-copper-magnesium systems, aluminum-magnesium-silicon systems, aluminum-zinc-magnesium systems, aluminum-zinc-magnesium-copper systems, and aluminum-lithium alloys.