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为改善合金中富铁相的形貌以降低其危害性,采用光学显微镜(OM)、扫描电镜(SEM)和WDW电子万能试验机等测试手段,研究稀土Y对Al-7Si-0.35Mg合金中富铁相组织形貌及合金力学性能的影响,亦对稀土Y变质富铁相的机制进行分析探讨。结果表明:稀土Y能促进富铁相异质形核和抑制其长大,并使其由粗大的块状、针片状转化为细小纤维状、球状;当稀土Y添加质量分数为0.3%时,变质效果最佳,其抗拉强度和伸长率分别为284 MPa和5.2%,比未添加稀土分别提高36%和58%;拉伸断口呈现大量致密、均匀韧窝的特征,表明合金具有良好的韧性,其断裂方式为塑性断裂。
In order to improve the morphology of the iron-rich phase in the alloy to reduce its harmfulness, using optical microscope (OM), scanning electron microscope (SEM) and WDW electronic universal testing machine to test the effect of rare earth Y on the iron content in Al-7Si-0.35Mg alloy Phase morphology and mechanical properties of the alloy, but also on the rare earth Y metamorphic iron-rich phase mechanism to explore. The results show that rare earth element Y can promote the heterogeneous nucleation and inhibit the growth of Fe-rich phase, and transform it from coarse massive and needle-like into fine fibrous and spherical shape. When the content of rare earth Y is 0.3% , The effect of metamorphism is the best. The tensile strength and elongation are 284 MPa and 5.2% respectively, which are increased by 36% and 58% respectively compared with the unadditioned rare earth. Tensile fracture shows a large number of dense and uniform dimples, indicating that the alloy has good Of the toughness, the fracture mode is plastic fracture.