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用挤压铸造工艺制备了莫来石短纤维(MULLITEF)增强马勒124合金(M124F)铝基复合材料,研究了该复合材料从室温到400℃高温的拉伸性能及热膨胀性能。试验结果表明,体积分数为17%的MULLITEF增强复合材料的300℃高温极限抗拉强度为228MPA,比其他短纤维或晶须增强相铝基复合材料提高15%以上;热膨胀系数(CTF)为16.5×10-6K。通过对3种试样的拉伸行为及SEM断口观察,分析了复合材料的静载破断机制,表明裂纹源主要生成于增强纤维与基体的复合界面上。
The MULLITEF reinforced M124F aluminum matrix composites were prepared by extrusion casting process. The tensile properties and thermal expansion properties of the composites from room temperature to 400 ℃ were investigated. The results showed that the ultimate tensile strength at 300 ℃ of MULLITEF reinforced composite with a volume fraction of 17% was 228 MPA, which was 15% more than that of other short fiber or whisker reinforced aluminum matrix composites. The thermal expansion coefficient (CTF) was 16.5 × 10-6K. Through the tensile behavior and SEM fracture observation of the three kinds of samples, the static load rupture mechanism of the composites was analyzed. It was found that the crack source was mainly generated at the composite interface between the reinforcing fibers and the matrix.