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Mechanism of Superplastic Deformation

ФИО: Emal Habib

Направление: Материаловедение

Научный руководитель: Anastasia Mikhailovskaya (Phd)

Институт: Институт экотехнологий и инжиниринга

Кафедра: Кафедра Металловедения цветных металлов

Академическая группа: MTM-14-1

In current technology the transportation industry and the automotive industry, in particular, have made increasing use of aluminum alloys in new vehicle construction. The primary incentive for using aluminum is the reduction in vehicle mass, which it makes possible. In automotive applications, mass reduction improves performance and fuel economy. There are many aluminum alloys used in industry today – over 400 wrought alloys and over 200 casting alloys are currently registered with the Aluminum Association. There are some general guidelines as to the most probable type of aluminum used in different applications, such as those mentioned above. However, it is very important to be aware that incorrect assumptions as to the chemistry of an aluminum alloy can result in very serious effects on mechanical performance.

Superplastic deformation refers to the ability of materials exhibiting high uniform elongation, when materials are pulled in tension while maintaining a stable microstructure. The fine grain size (typically less than 10 мm) and the thermal stability of the fine microstructure at high temperatures are two major prerequisites for achieving structural superplasticity. Superplastic forming (SPF) is widely used to fabricate complex parts in metallic sheets. However, the expansion of SPF into the fabrication of high-volume components in the commercial applications is currently limited, because the production of superplastic aluminum alloys is relatively expensive due to the complex thermo mechanical processing is typically necessary to make these materials superplastic. The occurrence of very large elongations, associated with an unusually high strain rate sensitivity of flow stress, in fine-grained polycrystalline materials – has been known for many years. It is referred to as superplasticity and has been the subject of much research. Despite the amount of effort devoted to the phenomenon, there remain uncertainties about the fundamental mechanism responsible for the high rate sensitivity.

In this research will prepare new alloy by melting Al4%Zn4%Mg3%Ni0.8%Cu0.3%Zr and study of the microstructure by LM, SEM in different stages, to analysis the difference and will perform the SPD test by preparing sets samples. Having strain rate of 1x10-2 and 5x10-2, 1x10-1 at temperature of 440C. To construct the stress-strain dependences.