Hot working Plastic forming of wrought metals by process operations such as forging, extrusion and rolling is performed under hot working or cold working conditions. Hot working is the plastic deformation and shaping of a metal above its recrystallisation temperature. A large number of dislocations are generated by strain hardening during the plastic forming of… Continue reading Hot and cold working of metal products
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Metal-forming processes
Forging Forging is a forming process used to strengthen and shape thick sections of cast metal. The process involves plastically deforming the metal under high compressive forces inside a die cavity, as shown in Fig. 7.2. Deformation usually occurs by repeated strokes or blows applied using hammers, mechanical presses or hydraulic presses. The metal is plastically deformed… Continue reading Metal-forming processes
Introduction
Metals are not used in their as-cast condition for safety-critical aircraft structures or load-bearing jet engine components. The use of cast metal in the primary structures of commercial airliners is virtually nonexistent, and it is used sparingly in military aircraft. Cast metals are used in a small number of nonstructural components on aircraft and helicopters,… Continue reading Introduction
Casting processes
There are many commercial processes to produce castings for processing into aircraft components. Casting processes are usually classified into two broad groups distinguished by the mould type: reuseable casting moulds and single-use casting moulds. This section briefly describes the processes commonly used for casting metals for aircraft structures and engines. The processes are permanent mould… Continue reading Casting processes
Casting of metal alloys
Shape and ingot castings Casting is the operation of pouring molten metal into a mould and allowing it to solidify. The pouring temperature is usually 50–180 °C above the melting point of the metal alloy. There are two broad classes of casting operations known as shape casting and ingot casting. Shape casting involves pouring the liquid… Continue reading Casting of metal alloys
Production of metal alloys
Addition of alloying elements to metal Metals are not used in aerospace applications in their pure (unalloyed) condition. Pure metals are too soft to use in aircraft structures and engines, and must be alloyed with other elements to produce high-strength materials. For instance, the addition of a few percent of copper to aluminium increases the… Continue reading Production of metal alloys
Introduction
There are many stages in the manufacture of aircraft structures and engine components using metals, and it begins with the production and casting of the metal alloy. The mechanical properties, corrosion resistance and many other properties that influence the selection and performance of metals in aircraft are determined by their method of production and casting.… Continue reading Introduction
Certification of aerospace materials
Pyramid approach to aircraft certification The certification of structural and engine materials is one of the most important issues with the testing and evaluation of new aircraft. Certification is also performed when new materials are used in major structural refits of existing aircraft, usually for life extension. Certification is essential to ensure the materials are… Continue reading Certification of aerospace materials
Environmental durability testing
Corrosion testing of metals One of the most damaging environmental effects of aerospace metals is corrosion. Corrosion of the metal alloys used in aircraft structures and engines occurs in many forms, including general corrosion, stress corrosion, pitting corrosion, crevice corrosion and exfoliation corrosion. The describes the corrosion properties of metals. There is no single, universal corrosion test; instead… Continue reading Environmental durability testing
Creep test
Creep is a plastic deformation process that occurs when materials are subjected to elastic loading for a long period of time, often at high temperature. Engineering materials do not plastically deform when loaded within the elastic regime for short times. However, when the elastic load is applied for a sufficient period the material eventually deforms… Continue reading Creep test