重力及微重力条件下Pd40Ni40P20合金凝固组织中溶质原子的分布特征

研究了Pd₄₀Ni₄₀P₂₀合金在重力（1g）及微重力（μg）条件下凝固组织中溶质原子的分布．与重力条件相比，微重力条件下凝固的样品组织中，初生相的P含量较低，而Pｄ的含量较高；共晶区域内的平均P含量较高而平均Pｄ含量较低．深入分析初生树枝晶一次枝晶间距Ｌ与冷却率υ以及固液界面前沿液相中溶质综合输运系数D的相互关系，发现地面条件下的固液界面前沿液相中溶质综合输运系数D_1g比空间的D_μg大1.7倍． 关键词：

SOLUTE DISTRIBUTION CHARACTERISTICS OF Pd40Ni40P20 ALLOY SOLIDIFIED IN MICROGRAVITY AND GRAVITY CONDITIONS

This paper studies the difference of solute distribution in microstructure of Pd₄₀Ni₄₀P₂₀ alloy solidified on board a Chinese Retrievable Satellite and on the ground.Compared with those in normal gravity condition(1g),it was found that P content was lower but Pd content was higher in the primary phase,however in the eutectic region P content increased but Pd content decreased in microgravity condition(μg).By evaluating the mass transport coefficients in both cases it can be concluded that the difference in solute distribution both in 1g and μｇ conditions was due to the existence of buoyancy convection in the ground-based experiments.