Al_2O_3短纤维/M124F复合材料的凝固组织

采用挤压铸造法制备了Al2O3短纤维增强M124F铝合金复合材料,并研究了其拉伸强度、基体凝固组织和界面。结果表明:用挤压铸造法制备的复合材料组织致密,纤维分布均匀,抗拉强度与M124F相比明显提高;基体组织的α-Al枝晶和Si相明显细化。分析表明,纤维的加入具有双重增强作用:高强度陶瓷纤维的介入增强了基体材料的力学性能;在凝固过程中,Al2O3短纤维阻碍了α-Al枝晶的生长,同时可作为Si相非自发形核的衬底,细化了基体组织,提高了复合材料的力学性能。纤维与基体间未发现界面生成物MgAl2O4。

Solidification microstructure of Al2O3 short fiber reinforced M124F composite

The tensile strength, solidification microstructure and interface in Al2O3f/M124F composites made by squeeze casting technique were investigated and analyzed. The results indicate that the compact structure and uniform distribution of the fibers can be achieved by squeeze casting, the tensile strength are significantly improved, and α-Al dendrite and Si phase in matrix structure are obviously refined. The analysis show that the addition of fibers have double enhancement.The intervention of high tensile-strength ceramic fiber reinforces the matrix material. The short alumina fibers retard the growth of α-Al dendrite and serve as the propitious sites for the heterogenous nucleation of Si phase during solidification, thus refining matrix microstructure and improving the mechanical properties of the composite furthermore.Interfacial products of MgAl2O4 are not observed between fiber and matrix.