**4. Summary**

The development of plastic forming processes as well as joining processes, such as FSW, is primarily determined by better mechanical properties of plastically processed magnesium alloys compared with castings. Designing the technology of plastic forming of structural elements made of magnesium alloys requires precise determination of the influence of the process parameters on the microstructure and consequently on the mechanical properties of the manufactured elements. This is of particular importance when designing products made of magnesium alloys for structural elements for the aviation industry. The selected results of plastic forming research carried out in material tests and technological processes, under laboratory or industrial conditions presented in this chapter, indicate that selected

magnesium alloys can be formed by plastic forming methods, especially by rolling, extrusion, and KOBO extrusion and forging. When forming AZ61, AZ80, and WE43 alloys, the temperature range is significantly limited, both at the beginning and the end of the deformation process. Therefore, to carry out plastic forming, especially forging, it is necessary to have devices that enable the process to be carried out in isothermal conditions. For AZ31 alloy, the range of temperatures of good formability is greater due to the greater tendency of this alloy to the recrystallization process. Thus, it is possible to manufacture AZ31 alloy products on conventional devices, but the obtained mechanical properties are less favorable than other magnesium alloys.

Magnesium-lithium alloys deserve attention due to their plastic formability, mechanical properties, and low specific weight, which makes them very attractive wherever lightweight and durable structures are desired. Elements manufactured by plastic processing of magnesium alloys and new technologies involving plastic deformation, including joint friction welding (FSW) technologies, are currently successfully implemented in various sectors of the economy.

Magnesium and its alloys are mainly used as a construction material (most often in the form of castings from magnesium alloys, but also plastically formed products), as an alloy additive to aluminum alloys, and for desulfurization of iron and steel. Due to the low specific mass and high relative strength, magnesium alloys in the form of castings or plastically formed products are used in such industries such as: aviation and aerospace, for the production of aircraft and rocket parts, including engine parts, gearbox components, hinges, fuel tanks, wing elements; automotive, for the production of, among others car rims, various types of housings, engine blocks, steering wheels, seat frames, windows and doors, body parts; sports and recreational, for bicycle parts and elements of various sports equipment articles; electronic, mainly for the production of various types of electronic equipment housings; medical, for strengthening elements in bone fractures. Examples of applications of magnesium alloys in the aviation industry include: Rolls Royce gear housing made of ZRE1 alloy Pratt & Whitney Canada PW535 engine housing made of ZE41 alloy, helicopter parts. In the automotive sector, the examples are steering wheel, boot lid; manufacturer GM, BMW engine block; cross section of the outer layer made of Mg alloy revealing the inner layer of Al alloy.

Now it is time for the successful application of magnesium-based materials. It is particularly important to promote exchange of information and discussion in which development trends and application potential in different fields such as the automotive industry and communication technology in an interdisciplinary framework [37, 72, 73].
