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This research studies pass numbers effect on microstructure and mechanical properties of magnesium alloy of AZ31C in the tubular channel angular pressing (TCAP) at the temperature of 300 °C. Pressing process has been carried out through four pass over AZ31C Magnesium tubes and in each pass the sample is exposed to Tensile and microhardness test and Metallography. The microstructure and mechanical properties of processed tube through one to four passes of TCAP process were investigated. Microhardness of the processed tube was increased to 62Hv after one pass from an initial value of 55 Hv. An increase in the number of passes from 1 to higher number of passes has not more effect on the microhardness. Yield and ultimate strengths were increased 1.97 and 1.49 times compared to as cast condition. Notably increase in the strength was achieved after two pass TCAP while higher number of passes has not more effect. Microstructural investigation shows notably decrease in the grain size to around 6 µm from the primary value of ~200 µm. microscope images show that the grain size is getting smaller by the first pass buy bigger in the next passes.

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In this article, it is tried to be mentioned the functional structure of production methods of ultrafine-grained (UFG) and nanograined tubes. As well as metallurgical and mechanical effects of these methods on the matter are fully investigated. Ultrafine grained materials contain grains with an average size of 100-1000 nm and if the grain size is less than 100 nm, the material is classified as nanograined material which have a lot of applications in different industries such as aerospace, automobile, military and medical. Generally, the methods presented in this paper has been done on common materials like aluminum and pure copper and magnesium alloy AZ91. Extremely large plastic deformations lead to ultrafine-grain or nearly nanomaterial in the severe plastic deformation (SPD) methods. Most severe plastic deformation methods for producing ultra-fine grain bulk, whereas in the past decade due to the increasing need tube components with high strength and good ductility, The research was conducted to produce UFG tubes. Advances in this field presented formally so that the advantages and disadvantages of each process are clearly comparable. The most important advantage of ultrafine-grain materials is an enhanced mechanical strength in comparison with their coarse grain counterparts. The microstructural reasons are discussed. Furthermore, this article reviews the refinement and deformation mechanisms, e.g. dislocation deformation mechanism, twin deformation mechanism, grain boundary sliding etc. of SPD methods.