耦合热力学相变路径预测Fe-C包晶合金宏观偏析

冯苗苗, 张红伟, 邵景霞, 李铁, 雷洪, 王强

Prediction of Macrosegregation of Fe-C Peritectic Alloy Ingot Through Coupling with Thermodynamic Phase Transformation Path

FENG Miaomiao, ZHANG Hongwei, SHAO Jingxia, LI Tie, LEI Hong, WANG Qiang

表1 计算所用合金物性参数

Table1 The alloy physical properties used in the calculation

Parameter description Symbol Unit Sn-5%Pb Fe-0.1%C Initial concentration c0 % 5.0 0.1 Initial temperature T0 oC 226 1550 Pure solvent melting temperature Tm oC 232 1538 Partition coefficient kp - 0.0656[5] 0.2[8] Liquidus temperature Tliq oC 224.86 1530.12 Liquidus slope m oC·%-1 -1.286[5] -80.579[8] Eutectic/peritectic temperature Te oC 181.41 1494.63 Liquid phase concentration at eutectic/peritectic point ce % 38.1 0.53 Solid phase concentration at eutectic/peritectic point ces % 2.2 0.09 Thermal expansion coefficient βT oC-1 6 × 10-5[5] 1 × 10-4[8] Solute expansion coefficient βs %-1 -5.3 × 10-3[5] 4 × 10-5[8] Reference concentration cref % 5.0 0.1 Reference temperature Tref oC 226 1550 Ambient temperature Text oC 25 25 Liquid density ρ kg·m-3 7000[5] 7020[8] Dynamic viscosity μl Pa·s 1.0 × 10-3[5] 6.2 × 10-3[8] Latent heat of solidification L J·kg-1 61000[5] 270000[8] Specific heat capacity at constant pressure cp J·kg-1·K-1 260[5] 680[8] Thermal conductivity of alloy λ W·m-1·K-1 55[5] 34[8] Liquid diffusion coefficient Dl m2·s-1 1 × 10-8[5] 1 × 10-8[8] Secondary dendrite arm spacing λ2 μm 65 50 Heat transfer coefficient α W·m-2·K-1 300 800 Time step Δt s 0.01 0.05