Microstructure and tensile properties of 6061 aluminum alloy prepared by friction rolling additive manufacturing

Ring-shaped components, as critical parts in the aerospace industry, require further optimization of their forming methods. In this study, Friction rolling additive manufacturing (FRAM) technique was employed to successfully fabricate a ring-shaped 6061 aluminum alloy component. A systematic study was conducted on the microstructure, tensile properties and formation mechanism of the component along the build direction. The results showed that the component fabricated by the FRAM exhibited a uniform hardness distribution, with an average hardness of 64.1 f 5.9 HV. The ultimate tensile strength (UTS) was 208 f 4.3 MPa, and the yield strength (YS) was 97 f 4.2 MPa, significantly higher than those of the base material (UTS: 128 f 4.9 MPa, YS: 59 f 4.1 MPa). The elongation of the FRAM-6061 alloy was 29.4 f 3.3%, which is similar to that of the base material (30.8 f 1.8%). During the additive manufacturing process, the repeated stirring action of the rotating tool facilitated the formation of a microstructure with an average grain size of 5.2 mu m at the interlayer and 22.8 mu m within the layers. The back stress strengthening mechanism generated by this microstructure is suggested to be the fundamental reason for the excellent coordination of strength and ductility in the FRAM-6061 aluminum alloy.