Microstructure And Properties Of72Cu-Zn-Al Alloy After Micro-alloying

A new type of high strength and high elasticity brass alloys is developed by micro-alloying in this research. The Ni, B, Co contents in72Cu-Zn-2.5Al alloy are optimized by orthogonal test, the Microstructure and Properties of72Cu-Zn-Al-0.4Co alloy with different Al content and by different processing-heat treatment is analyzed. In the final, and the Microstructure and Properties of72Cu-Zn-2.5A1-0.3Ti-0.5Ni-0.2B-0.4Co alloys in different states is researched. The results that are as follows:(1)The contents of Ni, B, Co in72Cu-Zn-2.5A1alloy are optimized by orthogonal test, in the orthogonal test, the optimal Ni, B, Co contents are0.5%、0.2%、0.4%. For the alloy with optimal composition after final annealing, the elastic modulus is120GPa, the tensile strength is610MPa, the yield strength is580MPa, the elongation is19.47%. For72Cu-Zn-2.5A1alloy’s elastic modulus, the Primary and secondary order isωB>ωNi>ωCo, and for tensile strength, it is ωCo> ωNi> ωB, and for elongation, it is ωCo> ωB> ωNi.(2)The alloy microstructure and mechanical properties of72Cu-Zn-Al-Co alloys with different Al contents are researched. The results show the mechanical properties of aluminum brass alloy with2.5%A1content is the best, in the60%cold-rolling deformation status, The tensile strength is828MPa, and the elastic modulus is114Gpa, and the elongation is4.0%, and the electrical conductivity is17.90%IACS. After final annealing, the tensile strength is659MPa, the elongation is21%, the elastic modulus is119GPa, the conductivity is21.69%IACS.(3)The cast microstructure of72Cu-Zn-2.5A1-0.3Ti-0.4Co alloy is constituted by a-phase, a small amount of13-phase and cobalt-containing compounds. The cobalt-containing compounds are mainly distributed on the grain boundary of a-phase. the results also show that the β-phase content will increase when the Al content is increase.(4)the recrystallization temperature of72Cu-Zn-2.5A1-0.3Ti-0.5Ni-0.2B-0.4Co alloy is360℃-370℃. This alloy exists low temperature annealing hardening effect, and the vickers hardness reached the peak after250℃annealing. The Co, B elements are formed coarse Co2B phase during casting, but formed tiny CoB phase during cold rolling.