不同Mn含量的铝青铜合金组织与性能

Microstructure and Mechanical Properties of Aluminum Bronze with Different Mn Contents

用熔铸法制备了Cu-12Al-2Ni-3Fe-x Mn(x=0,1,2,3,4;%,质量分数)合金,热处理工艺为920℃固溶2 h,540℃时效2 h。利用电子探针(EPMA)、扫描电镜(SEM)、万能试验机和摩擦磨损仪等设备对不同Mn含量的耐磨铝青铜的组织及性能进行研究后发现:合金中主要包含四种相,分别为k相、α相、β'相和γ相。随着Mn含量的增加,α相从条状转变成块状析出,γ相含量逐渐减少,k相弥散析出量先增加后降低,Mn含量为2%时,k相的弥散析出量达到最大。合金的抗拉强度和屈服强度随Mn含量的增加呈现出先增加后降低的趋势,在Mn含量为2%时抗拉强度和屈服强度分别达到最大值813.24和453.18 MPa,合金的延伸率随着Mn含量的增加而逐渐增大。随着时间的延长,同一合金的摩擦系数波动值逐渐减小;随着Mn含量的升高不同合金的摩擦系数变化量Δμ逐渐降低。Mn的添加降低了铝青铜合金的稳定摩擦系数和磨损量,Mn含量为2%时稳定摩擦系数和磨损量达到最小值,合金的摩擦形式也由粘着磨损转变为磨粒磨损为主。

Cu-12Al-2Ni-3Fe-x Mn（ x = 0,1,2,3,4; %,mass fraction） were prepared by melting method,the heat-treatment process was the combination of solution treatment at 920 ℃ for 1 h and ageing treatment at 540 ℃ for 2 h. The effects of Mn contents on microstructure and mechanical properties of aluminum bronze were studied by electro-probe micro analyzer（ EPMA）,scanning electron microscope（ SEM）,universal testing machine and friction and wear tester. The results showed that four phaes were included in the samples： k phase,α phase,β’ phase and γ phase. With the increase of Mn content,the appearance of α phase changed from strip into lump,the amount of γ phase reduced and the dispersive precipitation amount of k phase increased firstly and then decreased,attained the maximum when x = 2. The tensile strength and yield strength increased with the addition of Mn content first,decreased later,when Mn content was 2（ %,mass fraction）,the tensile strength and yield strength reached the maximum 813. 24 and 453. 18 MPa. The elongation of the samples increased with the increase of Mn content. With the extention of time,the same alloy’s friction coefficient fluctuating value decreased. The variation of the different alloy’s friction coefficient（ Δμ） also decreased with the addition of Mn content. The aluminum bronze with Mn had lower stable friction coefficient and higher wear resistance,the alloy with 2% Mn content had minimum friction coefficient and wear loss,the wear mechanism changed from adhesive wear to abrasive wear.