The Effect of RE on the Microstructure and Properties of Weld of 7075 Aluminum Alloy

In this paper 7075 aluminum alloy is studied as the object, through adding different percentages of the rare earth elements expecting to optimize alloy formula and find the optimal dosage of rare earth in order to improve the microstructure and properties of weld. The results show that when the rare earth content reaches 0.3%, alloys tensile strength comes to 388.39 MPa, and extensibility 18.22%. Compared with the control group, tensile strength is increased about 8.4%, extensibility about 14.7%, and the integrative mechanical performance is optimal. Metallographic research shows that accession of rare earth elements have perfect refinement effect to the microstructure of 7075 aluminum alloy and can improve the quality of weld.