论文部分内容阅读
采用拉伸性能测试、扫描电镜、透射电镜、深腐蚀、定量金相等技术手段研究了不同Fe含量的挤压铸造铝铜合金中富铁相演变规律及对合金拉伸断裂行为的影响。结果表明:随着Fe含量的增大,合金力学性能急剧下降,这主要是由于针状富铁相逐渐增多,富铁相体积分数的增多及尺寸的增大,同时铝基体里面的强化相减少。汉字状的α-Fe和Al6(Fe Mn)对高铁含量的合金性能危害性不大,这主要是由于汉字状的α-Fe和Al6(Fe Mn)中的枝晶臂与铝基体的界面结合能力更强,同时阻碍拉伸过程中裂纹扩展。而粗大针片状的β-Fe和Al3(Fe Mn)在拉伸过程中容易导致应力集中,成为裂纹的起源,同时在合金凝固过程中阻碍补缩通道形成铸造缺陷,从而恶化合金力学性能。挤压压力可以减少针状富铁相,并使针状富铁相高径比增大,同时细化富铁相尺寸。所有这些因素都能够减少富铁相本身开裂的趋势,同时增大富铁相与铝基体界面的结合力,从而提升合金力学性能。
The evolution of iron-rich phase in squeeze cast aluminum-copper alloy with different Fe content and the effect on the tensile fracture behavior of the alloy were investigated by tensile test, scanning electron microscopy, transmission electron microscopy, deep erosion and quantitative gold technique. The results show that with the increase of Fe content, the mechanical properties of the alloy decrease sharply, which is mainly attributed to the gradual increase of the needle-like iron-rich phase, the increase of the volume fraction of the iron-rich phase and the increase of the size, . Chinese character-like α-Fe and Al6 (Fe Mn) are not harmful to the properties of high-iron-content alloys, which is mainly attributed to the interfacial bonding of dendrite arms and aluminum matrix in α-Fe and Al6 (Fe Mn) More capable, while hindering the propagation of cracks during stretching. However, coarse needle-shaped β-Fe and Al3 (Fe Mn) easily lead to stress concentration and become the origin of cracks during the stretching process, meanwhile, it hinders the formation of casting defects during the solidification of the alloy and deteriorates the mechanical properties of the alloy. Extrusion pressure can reduce the needle-like iron-rich phase, and increase the aspect ratio of acicular iron-rich phase while refining the iron-rich phase size. All of these factors can reduce the tendency of the iron-rich phase itself to crack, increase the binding force between the iron-rich phase and the aluminum matrix interface, and enhance the mechanical properties of the alloy.