A Cu-1.5%Be alloy ribbon was prepared by single-roller rapid solidification method, and rapid solidification cooling rate was estimated according to the heat transport equilibrium equation. The microstructure and phase choice of the ribbon were characterized by powder X-ray diffraction and scanning electron microscopy. The results indicate that when the line speed of the roll surface is between 29. 93 m/s and 39. 19 m/s, the cooling rate can get to 9.80×105-1. 63×106 K/s . With the increase of roller speed and the decrease of eject pressure, the thickness and grain size of the ribbon gradually decrease. With increasing cooling rate, the effect of solute trapping is enhanced, the phase structure changes from multiphase to single phase. As the line speed reaches to 34. 54 m/s, the single phase α-Cu solid solution is formed in Cu-1. 5% Be alloy, and the microstrcture of the ribbon becomes fine so that nanocrystalline could be formed. The cross-section microstructure of the alloy ribbon along the direction vertical to the wheel surface is characterized by fine equiaxed, columnar and coarse equiaxed gain.%采用单辊旋淬法制备了快速凝固Cu-1.5％Be合金(Be质量分数1.5％)薄带.根据热传输平衡方程对快速凝固冷却速率进行了估算,并借助X射线衍射仪、扫描电子显微镜对该合金的微观结构及相选择进行了分析.结果表明:当辊面线速度在29.93～39.19 m/s范围内时,合金冷却速率可达到9.80×105～1.63×106 K/s;随着辊轮转速的提高和喷注气压的减小,合金条带厚度和晶粒度逐渐变小;随着冷却速率的增加,溶质截留效果显著,合金相结构由复相向单相转变,当辊面线速度达到34.54m/s时,Cu-1.5％Be合金可形成过饱和的α-Cu固溶体组织,且组织细小均匀,可获得纳米晶;条带横断面显微组织由接近辊面一侧的细小等轴晶区、中间的柱状晶区和靠近自由表面的等轴晶区组成.
展开▼
