This article provides an overview of fatigue and fracture resistance of aluminum alloys. It discusses the characteristics of aluminum alloy classes and the fracture mechanics of aluminum alloys. The article tabulates relative stress-corrosion cracking ratings for high-strength wrought aluminum products. It analyzes the selection of various alloys for stress-corrosion cracking resistance, including aluminum-lithium alloys, copper-free 7XXX alloys, and casting alloys. The article presents a list of typical tensile properties and fatigue limit of aluminum alloys. It also describes the effects of composition, microstructure, thermal treatments, and processing in fatigue crack growth of aluminum alloys.

Wrought heat treatable 7xxx alloys are more responsive to precipitation hardening than the 2xxx series alloys and can achieve higher strength levels, approaching tensile strengths of 690 MPa (100 ksi). This article provides an overview of key metallurgy, properties, and applications of the 7xxx aluminum alloy. It also illustrates the natural aging characteristics of 7050 aluminum sheet alloys at room temperature and relationships among commonly used alloys in the 7xxx series.

Alloy 710.0 is a natural-aging aluminum alloy produced by sand casting and suitable for highly stressed castings. This datasheet provides information on key alloy metallurgy, processing effects on physical and mechanical properties, and fabrication characteristics of this 7xxx series alloy.

In high-strength aluminum alloys, stress-corrosion cracking (SCC) is known to occur in ordinary atmospheres and aqueous environments. This article discusses the mechanisms of SCC in aluminum alloys, providing information on two main types of SCC models: those of anodic dissolution based on electrochemical theory and those that involve the stress-sorption theory of mechanical fracture. It reviews three different categories of experiments used to compare SCC performance of candidate materials for service. The categories are tests on statically loaded smooth samples, tests on statically loaded precracked samples, and tests using slowly straining samples. The article describes SCC susceptibility and ratings of SCC resistance for high-strength wrought aluminum products, such as 2xxx, 5xxx, and 7xxx series alloys, aluminum-lithium alloys, and 7xxx alloys containing copper.

This article provides an overview of the metallurgical effects on corrosion of different series of aluminum alloys (1xxx, 2xxx, 3xxx, 4xxx, 5xxx, 6xxx, and 7xxx) that are classified into two categories. The first category includes the effects from insoluble, intermetallic constituent particles generally formed from trace impurity elements that play a predominant role in pitting corrosion. The second category comprises the effects from precipitation of secondary phases and effects from solute remaining in solid solution on corrosion of aluminum.

This article discusses different heat treating techniques, including quenching, homogenizing, annealing, stress relieving, stress equalizing, quench hardening, strain hardening, tempering, solution heat treating, and precipitation heat treating (age hardening) for different grades of aluminum alloys, copper alloys, magnesium alloys, nickel and nickel alloys, and titanium and titanium alloys and its product forms.

Alloys 771.0 and 772.0 are high-strength, shock-resistant, aluminum sand-casting alloys that develop a high combination of physical and mechanical properties in the as-cast and room-temperature-aged conditions. This datasheet provides information on key alloy metallurgy, processing effects on physical and mechanical properties, and fabrication characteristics of these 7xxx series alloys.

This article summarizes a typical solution and aging heat treatments of 2xxx (Al-Cu), 6xxx (Al-Mg-Si), and 7xxx (Al-Zn-Mg) wrought alloys. It discusses the general aging characteristics and the effects of reheating of aluminum alloys. Typical examples of hardness and conductivity values for various aluminum alloy tempers are listed in a table. The article also describes the age hardening of Al-Cu (Mg) alloys, Al-Mg-Si alloys, and Zn-Mg-(Cu) aluminum alloys.

The powder metallurgy (PM) process is a relatively efficient and economic process that can be used to produce high quantities of aluminum components with a reasonable degree of precision and finds application in camshaft bearing cap (cam cap) production. The article discusses the production steps involved in cam cap manufacturing: powder production, compaction, sintering, repressing, and heat treatment. In addition, it reviews the R&D work involved in improving the structural properties of emerging aluminum alloy systems.

This article describes the general categories and metallurgy of heat treatable aluminum alloys. It briefly reviews the key impurities and each of the principal alloying elements in aluminum alloys, namely, copper, magnesium, manganese, silicon, zinc, iron, lithium, titanium, boron, zirconium, chromium, vanadium, scandium, nickel, tin, and bismuth. The article discusses the secondary phases in aluminum alloys, namely, nonmetallic inclusions, porosity, primary particles, constituent particles, dispersoids, precipitates, grain and dislocation structure, and crystallographic texture. It also discusses the mechanisms used for strengthening aluminum alloys, including solid-solution hardening, grain-size strengthening, work or strain hardening, and precipitation hardening. The process of precipitation hardening involves solution heat treatment, quenching, and subsequent aging of the as-quenched supersaturated solid solution. The article briefly discusses these processes of precipitation hardening. It also reviews precipitation in various alloy systems, including 2xxx, 6xxx, 7xxx, aluminum-lithium, and Al-Mg-Li systems.

Heat treatment of aluminum alloys frequently refers to the heat treatable aluminum alloys that can be strengthened by solution treatment, quenching, and subsequent hardening. This article introduces the general metallurgy of strengthening aluminum alloys by heat treatment. It discusses various heat treatable alloying elements, such as copper, chromium, iron, magnesium, silicon, zinc, and lithium. The article describes the age-hardening treatments and generalized precipitation sequence for aluminum alloys. It reviews the solution heat treatment in terms of solution heating time and temperature, as well as high-temperature oxidation. The article also discusses quench sensitivity, vacancy loss, grain-boundary precipitates, and quench delay for the heat treatment of aluminum. It concludes with a discussion on the deformation of aluminum alloys prior to aging.

The development of aluminum alloys has progressed along two tracks: heat treatable and non-heat treatable. The Aluminum Association alloy composition limits and product temper are defined for major alloying elements. This article summarizes the historical evolution of the different series of wrought aluminum alloys (1xxx to 8xxx) and discusses their applications based on the alloying system introduced by the Aluminum Association.

High-volume additive manufacturing (AM) for structural automotive applications, along the lines of economically viable technologies such as powder metallurgy, castings, and stampings, remains a lofty goal that must be realized to obtain the well-known advantages of AM. This article presents two key opportunities for AM related to automotive applications, specifically within the realm of metal laser powder-bed fusion: alloys and product designs capable of high throughput. The article also presents the general methodology of alloy development for automotive AM. It provides examples of unique designs for reciprocating components in elevated-temperature applications that are also exposed to demanding tribological conditions. The article also discusses the future of AM for automotive applications.

This article describes the influences of the operational environments of U.S. Navy aircraft during corrosion-control process. The most widely used materials in airframe structures and components, such as aluminum, steel, titanium, and magnesium alloy systems, are reviewed. The article provides information on the inspections steps, corrosion-control issues, and corrosion-prevention strategies for naval aircraft. It contains a table that lists typical locations of corrosion on the aircraft. The article also provides examples of aircraft corrosion damage.

This article provides information about the selection of brazing processes and filler metals and describes the brazing (heating) methods, including manual torch brazing, furnace brazing, induction brazing, dip brazing, resistance brazing and specialized brazing processes such as diffusion and exothermic brazing. The article explains joint design, filler materials, fuel gases, equipment, and fluxes in the brazing methods. The article also describes the brazing of steels, stainless steels, cast irons, heat-resistant alloys, aluminum alloys, copper and copper alloys, and titanium and titanium alloys.

Aluminum and its alloys are highly corrosion resistant, protected by a self-healing oxide film that effectively passivates the underlying surface. This article examines the various processes by which the protective layer can be breached and the types of corrosion that can occur. It describes pitting, galvanic, and atmospheric corrosion as well as stress-corrosion cracking, corrosion fatigue, and erosion corrosion. It also covers intergranular, exfoliation, filiform, deposition, and crevice corrosion and special cases of corrosion in soils, seawater, and automotive coolant systems. The article provides an extensive amount of data as well as information on coatings, claddings, and cathodic protection methods; the effects of composition, microstructure, and surface treatments; and the compatibility of aluminum with food and various household and industrial chemicals.

This article discusses surface engineering of nonferrous metals including aluminum and aluminum alloys, copper and copper alloys, magnesium alloys, nickel and nickel alloys, titanium and titanium alloys, zirconium and hafnium, zinc alloys, and refractory metals and alloys. It describes various techniques to improve functional surface properties and enhance the appearance of product forms. The article discusses various cleaning and finishing techniques such as abrasive blast cleaning, polishing and buffing, barrel burnishing, chemical cleaning, pickling, etching and bright dipping, electrochemical cleaning, mechanical cleaning, and mass finishing. It also examines coating processes such as plating, anodizing, chemical conversion coating, and thermal spray, and concludes with a discussion on oxidation-resistant coatings for refractory metals.

Brazing technology is continually advancing for a variety of metals including aluminum and its alloys and nonmetals. This article discusses the key physical phenomena in aluminum brazing and the materials for aluminum brazing, including base metals, filler metals, brazing sheet, and brazing flux. It describes various aluminum brazing methods, such as furnace, vacuum, dip, and torch brazing. Friction, flow, induction, resistance, and diffusion brazing are some alternate brazing methods discussed. The article reviews the brazing of aluminum to ferrous alloys, aluminum to copper, and aluminum to other nonferrous metals. It also discusses post-braze processes in terms of post-braze heat treatment and finishing. The article concludes with information on the safety precautions considered in brazing aluminum alloys.

This article discusses the properties of aluminum surface and the applications of aluminum alloys. It explains the effects of trace elements on aluminum alloys. The article considers microstructural development of aluminum in terms of the surface and explains how it will impact corrosion resistance and surface treatment. It describes the thermodynamics of equilibrium oxidation processes and non-equilibrium corrosion processes. The article provides a discussion on aluminum oxidation under atmospheric and dynamic conditions. It presents the potential/pH (Pourbaix) diagram for aluminum under atmospheric and dynamic conditions. The article also explains the polarization effects during the formation of stable aluminum oxide under dynamic conditions. It concludes with information on the designation system for aluminum finishes.

Metal-matrix composites (MMCs) are a class of materials with a wide variety of structural, wear, and thermal management applications. This article discusses the primary processing methods used to manufacture discontinuous aluminum MMCs, namely, high-pressure die casting, pressure infiltration casting, liquid metal infiltration, spray deposition, and powder metallurgy methods. It describes the processing of continuous fiber-reinforced aluminum, discontinuously, reinforced titanium, and continuous fiber-reinforced titanium. The article concludes with information on work done to develop magnesium, copper, and superalloy MMCs.