Study On The Microstructure And Mechanical Properties Of Al-Mg Aluminum Alloy Through The Continuous Extrusion Forming

For its moderate strength, good processing performance and excellent weldingperformance, Al-Mg alloy has been widely used in the electrical industry. This thesisresearched on the possibility of producing the Al-Mg alloy rod of the copper cladA1-Mg alloy wire through continuous extrusion forming. It studied the effects of thecopper elements and the continuous extrusion forming processing technique on themicrostructure and mechanical properties of Al-Mg alloy by means of themetallographic microscope, SEM, transmission electron microscopy (TEM) and tensiletesting.(1) The copper can enhance the strength and plastic property of Al-Mg alloy byfiner the alloy microstructure and generating two strengthening precipitates-θ (Al2Cu)and S (Al2CuMg) phase and making the precipitates refinement and uniformlydistributed; the composition of target alloy is Al-(1.1~1.3)Mg-0.2Cu; deeper dimplescan be seen in the fracture morphology; the microstructure of alloy containing copperis more stable after annealing; fewer grains grow up significantly; second phase iscoarser, irregular and uneven distribution in alloy without copper, and coarse phasecontaining Si, Fe, O impurities can be found in it.(2) Compared to the drawing and then anneal process, the continuous and heavyshear deformation under continuous extrusion forming resulted in finer and moreuniform structure, it remarkably improved the tensile elongation but slightly lower thestrength of the alloy; the deformation temperature is higher under continuous extrusionforming, which promote dynamic recovery and dynamic recrystallization; thedislocation density reduce; the second strengthening phase, impurities and insolubleprecipitates distribute uniformly, and effectively pins dislocations; equated dimpleswith uniform size and deeper depth can be seen in the fracture morphology. Producingthe copper-added Al-Mg alloy rod under continuous extrusion forming provided a goodtensile property for the following plastic working.