Fabrication and Properties of Tungsten Single Crystals. Part I. Growth of Single Crystal Tungsten to Be Used for Rolling into Single Crystal Sheet. Part II. Rolled Single Crystal Tungsten Sheet

摘要

Effort was made to find a method for deforming single crystals of tungsten such that monocrystallinity is maintained throughout the deformation process. The technology of deformation and joining of tungsten single crystals has reached the point where simple items of hardware which retain their single crystal character can be fabricated. An item of hardware which is also a single crystal is desirable in certain applications for two reasons. The recrystallization phenomenon with its associated brittleness is absent. Thus, the single crystal will remain ductile even if heated to the melting point. Because of the single crystallinity of material, it can be welded by a state-of-the-art technique and maintain its single crystallinity even in the weld bead. Thus recrystallization and brittleness associated with weldments are also avoided. Cold deformation of tungsten single crystals requires extreme care in its present state of development. The starting single crystal boules from which billets are fabricated must be of high purity and of low dislocation concentration and lineage.