摘要
本文应用 PBC 理论证实了 MC 碳化物从 Ni 基高温合金熔体中生长的理想形貌是以{111}面为外表面的八面体.认为 MC 的一种生长基元为由金属原子和周围六个碳原子组成的八面体配位体,在近平衡条件下MC 碳化物的晶体生长机制是该配位体沿晶体的{111}面层状生长.
The carbides of MC formed during solidification of Ni-base sup-eralloys exist in the form of blocky or Chinese-script type morphology.Experiments show that both initial morphology in normal solidification conditionand final morphology near equilibrium condition are octahedral blocks.Thetheoretical form of MC carbide growing from superalloy melt is considered asoctahedral shape enclosed by {111} faces according to analysis of PBC(PeriodicBond Chain)theory.It has also inferred that one of growth units of MC carbidemay be octahedral molecule consisting of a metal atom su(?)ounded by six carbonatoms.The stack sketch of these growth units is layer growth mechanisms on{111} faces,which is verified by observation of SEM after ion bombarding forthe surface of Mc carbide.
基金
国家自然科学基金
5870064
关键词
NI基高温合金
MC碳化物
生长机制
superalloy
carbide
crystal growth morphology
growth mechanism
