Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio
Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio
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DOI：
10.1016/j.msea.2013.09.043
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发表时间：
2013-12
期刊：
影响因子：
6.4
通讯作者：
Weiweng Zhang;B. Lin;Jianlei Fan;Datong Zhang;Yuanyuan Li
中科院分区：
文献类型：
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作者：
Weiweng Zhang;B. Lin;Jianlei Fan;Datong Zhang;Yuanyuan Li
采用挤压铸造法制备了不同Mn/Fe比的Al-5.0 wt% Cu-0.5 wt% Fe合金。采用拉伸试验、图像分析、扫描电镜（SEM）、X射线衍射（XRD）、电子探针（EPMA）和透射电镜（TEM）等测试手段研究了T5热处理态合金的显微组织和力学性能。结果表明，经T5热处理后，β-Fe（Al 7 Cu 2Fe）相稳定，其针状形貌得以保持。但汉字AlmFe、α-Fe或Al 6（FeMn）部分转变为新的汉字富Cu α（CuFe）（Al 7 Cu 2Fe或Al 7 Cu 2（FeMn）），由于α（Al）基体中Cu含量的减少，对合金的力学性能不利。最佳Mn/Fe比取决于富Fe金属间化合物的形貌、θ′和T（Al 20 Cu 2 Mn 3）的体积分数、α（Al）枝晶尺寸和孔隙率。过高的Mn/Fe比会使合金的孔隙率和富铁金属间化合物总量增加，从而使合金的力学性能恶化。当Mn/Fe比分别为1.6和1.2时，压力分别为0 MPa和75 MPa时，针状β-Fe相完全转变为汉字状富Fe金属间化合物。当Mn/Fe比为1.2、施加压力为75 MPa时，T5合金的抗拉强度、屈服强度和延伸率分别达到395 MPa、335 MPa和14%。
The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al7Cu2Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese script AlmFe, α-Fe or Al6(FeMn) partially transform to a new Chinese script Cu-rich α(CuFe) (Al7Cu2Fe or Al7Cu2(FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al20Cu2Mn3), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively.