Effect of sintering technology on mechanical properties of Cu-20Zn brass

Cu-20Zn brass was prepared by powder metallurgy(PM) method.The PM samples were sintered by two processes separately as below: the first is rapid heating to 550 ℃ pre-sintering for 50 min,and then sintering at 860 ℃ for 50 min.The second is slow heating from 100℃ to 750 ℃ in 200 min,and then sintering at 870 ℃ and holding for 1 h.The results show that there are a lot of pores with irregular shape in the alloy after sintered by the first process.After sintered by the second process,since the pre-sintering time is prolonged and the heating speed is slowed down,the number of pores decreases in the alloy,the density and hardness of the sintered alloys increase,and the elongation of them increase greatly as well;however,the effects of grain boundary strengthening decrease because of the growth of grains,which results in the strength of Cu-20Zn alloy decrease.Cu-20Zn alloy sintered by the second process has good comprehensive mechanical properties.The density,hardness,tensile strength and elongation are 8.12 g/cm3,86HRH,242 MPa and 27.3%,respectively.All of these properties exceed the Japanese industrial standard(JIS) and Chinese national standard(GB).