Liquid metals - diffusion and solidification

液态金属和合金中原子的运动，称为液态扩散，是一个重要的传输过程，发生在铸造、焊接以及所有涉及熔化和凝固的过程中。液体扩散部分地决定了合金元素的分布、从熔融状态固化的任何部件的微观结构和宏观结构，这反过来又有助于铸件和焊接部件的强度和韧性。尽管液体扩散很重要，但由于缺乏准确、可靠的数据，对构成扩散过程的原子运动知之甚少。直到最近，对流掩盖了原子运动由于扩散单独。在微重力环境下进行的实验中，获得的不涉及对流输运的准确结果很少，但微重力环境的费用和可进入性限制了可以获得的信息量。它最近已被证明，准确的液体扩散的结果，可以在单位重力在一定条件下，并建议利用这些条件来获得数据的变量范围很广，从而提供了一个数据库，从该理论的液体扩散可能会发展。

The motion of atoms in liquid metals and alloys, known as liquid diffusion, is an important transport process that occurs in castings, welds, and all processes that involve melting and solidification. Liquid diffusion determines, in part, the distribution of alloying elements, the microstructure and macrostructure of any component that was solidified from a molten condition which in turn contribute to the strength and toughness of castings and welded components. Despite the importance of liquid diffusion, little is known concerning the atomic motions that comprise the diffusion process because of the paucity of accurate, reliable data. Until recently, convective currents have masking the atomic motion due to diffusion alone. A very few accurate results free from convective transport have been obtained from experiments performed in microgravity but the expense of and accessibility to the microgravity environment limits the amount of information that can be obtained. It has recently been shown that accurate liquid diffusion results can be obtained in unit gravity under certain conditions and it is proposed that these conditions be utilized to obtain data for a wide range of variables thus providing a data base from which a theory for liquid diffusion may be developed.