重熔温度和搅拌时间对Al-B_4C复合材料显微组织的影响研究

Effect of Remelting Temperature and Stirring Time on the Microstructure of Al-B_4C Composites

研究了重熔温度和搅拌时间对Al-B_4C复合材料显微组织的影响。通过扫描电子显微镜和X射线衍射仪对显微组织和物相组成进行表征。结果发现:同原始材料相比,材料在750℃保温1h之后,基体中Al_3Ti相消失,B_4C颗粒表面长出大量针状TiB_2相;在800℃保温1 h之后,基体中出现新相AlB_2颗粒;当温度进一步升高,界面反应加剧,AlB_2颗粒增加,B_4C颗粒被液态Al严重侵蚀;材料在750℃保温45min熔化后开始搅拌,当搅拌时间达到30 min时,基体中出现AlB_2颗粒,随着搅拌时间的延长,AlB_2颗粒增加,界面反应加剧。

The effect of remelting temperature and stirring time on the microstructure of Al-15%(wt) B4C composite was investigated. Scanning electron microscope and X-ray diffraction were used to examine the microstructures and reaction products. The results showed that there was no obvious difference between original sample and specimens holding at 750 ℃ for 1 h,except for the disappearance of the Al3Ti particles, and the appearance of many coarse TiB2 grains generated at the interface. However, for specimens holding at 800 ℃ for 1 h, AlB2 phase appeared around B4C particles. When the temperature was higher, AlB2 particles increased rapidly, the interface reaction was more serious and B4C particles were seriously eroded by molten aluminum. The composite was stirred after heating at 750 ℃ for 45 min. When the stirring time was up to 30 min, the lath-shaped AlB2 phase was obviously generated in the matrix. With the increase of stirring time, the reaction products were also increased.