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利用垂直Bridgman法结合液态金属冷却法在恒定的液相温度梯度(GL=250 K/cm),凝固速率由2μm/s到490μm/s之间对Al-40%Cu合金进行定向凝固实验。结果表明:Al-40%Cu合金在低速下组织为全耦合的片层共晶结构,但当速率增加时,合金组织中出现一定量的初生Al2Cu相,凝固速率对合金共晶片层间距的影响通过实验结果分析。在实验的定向凝固速率范围内,发现平界面和胞状界面生长的两种共晶界面形态,并且不管是在哪种共晶界面形态下,共晶层片间距和凝固速率的关系都符合函数关系:λ2ν=常数,利用JH模型计算得到常数C的值为12.85μm3/s。
Al-40% Cu alloy was directionally solidified by vertical Bridgman method combined with liquid metal cooling method at a constant liquidus temperature gradient (GL = 250 K / cm) and solidification rate from 2μm / s to 490μm / s. The results show that the Al-40% Cu alloy is a fully coupled lamellar eutectic structure at low speed. However, when the rate increases, a certain amount of primary Al2Cu phase appears in the alloy and the effect of solidification rate on the eutectic spacing Through the analysis of experimental results. In the range of experimental directional solidification rate, two eutectic interfacial morphologies of flat interface and cell interface were found, and the relationship between the eutectic layer spacing and the solidification rate was in accordance with the functional relationship : λ2ν = constant, calculated using the JH model C value of 12.85μm3 / s.