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采用脉冲磁场技术制备了半固态Al-4.5Cu合金坯料,考察了冷却速度和脉冲频率对半固态坯料初生α-Al相形貌和尺寸的影响。结果表明,利用脉冲磁场处理可以制备出初生α-Al相为细小的近球状颗粒的半固态Al-4.5Cu合金坯料。初生α-Al相平均晶粒尺寸和平均形状系数分别随着冷却速度的减小和脉冲频率的增加而相应的减小和增加。但当冷却速度减小到20℃/min,脉冲频率增大到10Hz时,半固态组织有所粗化。当冷却速度为40℃/min,脉冲频率为6Hz时,半固态Al-4.5Cu合金坯料初生α-Al相平均晶粒尺寸最小,形貌最为圆整,适合于半固态成形。
Semi-solid Al-4.5Cu alloy billets were prepared by pulsed magnetic field technology. The effects of cooling rate and pulse frequency on the morphology and size of primary α-Al phases in semi-solid billets were investigated. The results show that semi-solid Al-4.5Cu alloy billet with fine primary particles of α-Al phase can be prepared by pulsed magnetic field. The average grain size and average shape factor of primary α-Al phase decrease and increase with the decrease of cooling rate and pulse frequency respectively. However, when the cooling rate is reduced to 20 ℃ / min and the pulse frequency is increased to 10Hz, the semisolid microstructure is coarsened. When the cooling rate is 40 ℃ / min and the pulse frequency is 6Hz, the average primary α-Al grain size of the semi-solid Al-4.5Cu alloy billet is the smallest, and the morphology is the best. It is suitable for semi-solid forming.