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本文通过实验研究了金属系层片状共晶合金S—L界面前沿扩散边界层的溶质分布。实验结果表明:在液淬瞬间,S—L界面存在一瞬间凝固速度,它比稳态凝固过程中测得的数据在本实验的条件下约大一个数量级;在Jackson—Hunt的理论计算公式中的F_0项中,S_β/S_α不能仅由平衡相图 (C_β/C_α) 来决定,它还与组成共晶合金两组元的比重有关,本文推导出一个带比重因子的新的F_0表达式,即:F_0=C_αρ_A+C_Bρ_B/C_αC_β(ρ_B-ρ_A)
In this paper, we study the solute distribution in the frontier diffusion boundary layer of S-L interface of eutectic alloy. The experimental results show that there is an instantaneous solidification rate at the moment of liquid quenching, which is about one order of magnitude larger than that measured in the steady-state solidification process. In Jackson-Hunt’s theoretical formula In the F_0 term, S_β / S_α can not be only determined by the equilibrium phase diagram (C_β / C_α), but also depends on the specific gravity of the two components forming the eutectic alloy. In this paper, a new F_0 expression with a specific gravity factor is deduced. That is: F_0 = C_αρ_A + C_Bρ_B / C_αC_β (ρ_B-ρ_A)