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采用真空感应磁悬浮熔炼法制备Ti-47Al-2Cr-2Nb-xB(x=0,0.15,0.8,1.5)(at%)十字形不同壁厚(2、5、10、20mm)的铸件。借助体视显微镜、扫描电子显微镜(SEM)对铸件的组织进行分析,研究硼含量和冷却速度对铸件硼化物形态、晶粒细化效果的影响。结果表明:硼含量越高,冷却速度越快,细化效果越好。随着硼含量的增加,硼化物的形态从弯曲条带状逐渐转变为短棒状或片状。Ti-47Al-2Cr-2Nb-0.8B铸件硼化物尺寸随冷却速度的降低而减小,Ti-47Al-2Cr-2Nb-0.15B和Ti-47Al-2Cr-2Nb-1.5B铸件硼化物随冷却速度的变化规律不明显。
Ti-47Al-2Cr-2Nb-xB (x = 0,0.15,0.8,1.5) (at%) cruciform castings with different wall thicknesses (2, 5, 10, 20mm) were prepared by vacuum induction magnetic levitation method. The microstructure of castings was analyzed by stereomicroscope and scanning electron microscope (SEM), and the effects of boron content and cooling rate on the morphology and grain refinement of the borides were investigated. The results show that: the higher the boron content, the faster the cooling rate, the better the refining effect. With the increase of boron content, the morphology of boride gradually changes from curved strip to short rod or sheet. The size of boride in Ti-47Al-2Cr-2Nb-0.8B castings decreases with the decrease of cooling rate. The borides of Ti-47Al-2Cr-2Nb-0.15B and Ti-47Al- The law of change is not obvious.