316L激光粉末床熔覆IN718偏析带形成过程的模拟

沈盟凯, 董太宁, 葛鸿浩, 石新升, 张群莉, 刘云峰, 姚建华

Simulation of the Formation Mechanism of Segregation Bands During IN718 Cladding on 316L Using Laser Powder Bed Fusion

SHEN Mengkai, DONG Taining, GE Honghao, SHI Xinsheng, ZHANG Qunli, LIU Yunfeng, YAO Jianhua

表1 模型中的热物性参数[23]

Table 1 Thermophysical parameters in the model[23]

Parameter Symbol Value Unit Melting point of pure Fe Tf 1805.15 K Reference densities of liquid and solid ρl, ρs 8000 kg·m-3 Specific heat cp 500 J·kg-1·K-1 Thermal conductivity of solid kqs 19.2 W·m-1·K-1 Thermal conductivity of liquid kql 209.2 W·m-1·K-1 Latent heat Δhf 250000 J·kg-1 Viscosity μl 0.0042 kg·m-1·s-1 Volume heat-transfer coefficient H* 1 × 109 W·m-2·K-1 Temperature coefficient of surface tension ∂γ / ∂T -4.3 × 10-4 N·m-1·K-1 Maximum nucleation density nmax 1 × 109 m-3 Average nucleation undercooling ΔTn 15 K Nucleation undercooling deviation ΔTσ 5 K