Fe元素对ZA27合金显微组织和力学性能的影响

在ZA27合金中添加0.5%~2%的Fe元素,利用金相、扫描电镜(SEM)、能谱分析(EDS)、X射线扫描(XRD)、拉伸实验等测试手段,研究Fe含量对ZA27合金显微组织和力学性能的影响。结果表明:不同Fe含量的ZA27合金基体组织均由富铝的α相和富锌的η相组成。Fe元素以FeAl3金属间化合物的形式分布于基体中。随Fe含量增加,FeAl3的含量增多、尺寸增大。FeAl3能阻碍晶界迁移,起到细化枝晶的作用。研究还发现,室温下,随Fe含量增加,ZA27的强度和伸长率均降低;150℃高温下,Fe含量为1.5%左右的ZA27合金抗拉强度达192.75MPa,比未加Fe元素的ZA27合金提高约54.4%,伸长率达15.65%,从而获得兼具高强度和高塑性的高温ZA27合金。

Effect of Fe on microstructure and mechanical properties of ZA27 alloy

0.5%~2% of Fe element was added into ZA27 alloy.Effect of Fe addition on microstructure and mechanical properties of ZA27 alloy was investigated by optical microscopy,scanning electron microscopy,energy dispersive spectrometry,X-ray diffractometry and tensile tests.The results show that all the matrix of ZA27 alloys with different Fe contents mainly consist of aluminum-rich α phase and zinc-rich η phase.Fe disperses in matrix by forming of FeAl3 intermetallics whose content and size increase with increasing of Fe content.Since FeAl3 can impede the migration of the grain boundaries,inhabit the grain growth and also pin the dislocations,the high-temperature tensile strength of ZA27 alloy can be significantly improved.The strength and elongation of ZA27 alloy decrease with increasing the addition of Fe at room temperature.The alloy with mass fraction of 1.5% Fe exhibits a good combination of high tensile strength of 192.75 MPa which is 54.4% higher than that of Fe-free alloy and elongation of 15.65% at the temperature of 150 ℃.