On some causes of crushing fracture of Al-6%Mg alloy pieces

The reasons for the occurrence of increased tendency to brittle fracture at normal temperatures of the material of pressed bars made of aluminium-magnesium Al-6%Mg alloy AMг6 are considered. By analyzing metallography and comparing hardness, materials from different years of production are compared. It is shown that one of the reasons for the material’s tendency to brittle fracture may be the increased content of excess intermetallic compounds in it, which is a function of various technological influences from the preparation of the initial melt to the production of pressed rods. The mechanism of formation of excess phases and ways of limiting this process are described. The contradiction between the technical recommendation “ТР 50-31-70”, which indicates the need for homogenization of ingots at 500 °C for at least 3...6 hours, and the industry standard “ОСТ 92-1019–81”, where to increase the ductility of rolled and pressed materials from Al-5 %Mg "AMг5" and Al-6 %Mg "AMг6" alloys, it is prescribed to anneal them at 380...440 ? for no longer than 3 hours.
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