Friction stir welding of aluminium and copper alloys

ABSTRACT

Sheet blanks from copper (M1) and aluminium alloys (AD1, AD32) with a thickness of 3 mm are joined in butt joints and overlap, butt joints – overlap joints by friction stir welding (FSW). The microstructure, mechanical properties and phase components of the welded joints obtained by the FSW are studied by using various methods of metal physics analysis, including X-ray diffraction, mechanical tensile and bending tests, etc. The test results showed that high quality of the welded joint can be achieved when tool rotation is 900 min–1 and the welding speed is 25 mm/min when the angle of tool inclination angle is 3°. The maximum value of the tensile strength is about 66 MPa. Copper and aluminium alloys are formed due to solid-phase mixing in the superplastic state (SPS), forming a characteristic shear-strip-layered structure with alternating layers in zone of weld seam cores (WSC). A mixed structure with characteristic fragments of Cu and Al is formed on the aluminium side on the side of the WSC. New intermetallic phases were not detected in the WSC centre.

KEYWORDS:

• Copper alloy
• aluminium alloy
• microstructure
• mechanical properties
• phase
• composition
• friction stir welding