铁含量对ZCuSn3Zn8Pb6Ni1FeCo合金组织与性能的影响

采用砂型铸造方法,制备了不同Fe含量的ZCuSn3Zn8Pb6Ni1FeCo合金.利用光学显微镜、拉伸测验、SEM和EDS能谱等分析测试手段,研究Fe含量对合金组织与性能的影响.结果表明:合金组织以α{Cu,Sn,Zn}为基体,并存在硬脆相δ-Cu_(10)Sn_3,铅以单质形式析出;强化析出相主要有α-Fe和γ-Fe,以及CoCu_2Sn、Fe_3Co_7、Fe_Zn_9等;强化机制符合Orowan机制;当铁含量为1wt%时.以细小弥散颗粒状析出为主(平均直径5-15nm),抗拉强度和伸长率分别为350MPa和12.5%;随着铁含量的增加,除细小弥散析出外,较大颗粒状和粗大颗粒析出数量增多,析出物平均直径增大,综合力学性能指标大幅下降;当铁含量为4wt%时,析出颗粒尺寸达到4～10μm,晶界富集粗大析出相,伸长率下降到5%.

Effects of iron on microstructure and properties of ZCuSn3Zn8Pb6Ni1FeCo alloy

ZCuSn3Zn8Pb6Ni1FeCo alloy samples with different amount of Fe were prepared by sand casting.The effect of Fe content on properties and microstucture of the alloy was investigated by means of optical microscope, SEM, EDS analysis and tensile test. The results show that the microstructure of the alloy consists of matrix α-{Cu,Sn,Zn}, precipitates of α-Fe,γ-Fe,CoCu2Sn,Fe3CoT, Fe4Zn9, brittle phase δ-Cu10Sn3 ,and Pb particles. The strengthening mechanism obeys Orowan mechanism. Fine precipitates of 5 ～ 15nm dispersively distributed in the alloy with 1wt%Fe is observed and its tensile strength and elongation are 350MPa and 12.5% respectively. With increase of Fe content, the precipitates coarsens, as a result, the comprehensive mechanical property deteriorates. When Fe content reaches to 4wt%, the precipitates increase to 4～10μm, elogation of the alloy decreases to 5%.