The lead-free and free cutting 2011 aluminum alloy bars were prepared by Bi and Sn substituted for Pb. The effects of Bi content on microstructure

mechanical properties and cutting properties of 2011 aluminum alloy bar were investigated by metallographic microscope

scanning electron microscope

tensile testing machine and high-speed lathe. The results reveal that Bi mainly exists in form of BiSn eutectic phase in aluminum alloy bars when the Bi content is 0.2%. When the content of Bi is more than 0.2%

Bi exists in form of Bi phase and BiSn eutectic phase. The higher the Bi content is

the more the amount of Bi phase and BiSn eutectic phase are

so the cutting performance of aluminum alloy bar is improved and the chip length is decreased. However

the tensile strength and elongation of aluminum alloy bar are decreased slightly with the increase of Bi content. When the Bi content is increased to 1%

the average chip length of aluminum alloy bar

the tensile strength and the elongation are 3 mm

283.5 MPa and 25.9%

respectively.