铀从熔化状态凝固后冷却到室温,要经过两次同素异形转变,同时伴随着体积的变化。因而,采用熔态凝固或相变的方法不能获得完整的单晶体,只能得到类似多边化结构的不完整单晶体,称为假单晶体。如果将假单晶进行适度的变形,然后在α相区内退火,可以得到完整的单晶体。虽然制备单晶体是一件比较麻烦的事情,但是用单晶体作为样品来研究金属的 Uranium solidified from the melting state after cooling to room temperature, to go through two allotropic transformation, accompanied by changes in volume. Therefore, the use of molten solidification or phase change method can not get a complete single crystal, can only be obtained similar to the multilateral structure of the single crystal, called pseudocrystals. If the pseudo-single crystal is moderately deformed and then annealed in the α-phase region, a complete single crystal can be obtained. Although the preparation of a single crystal is a troublesome thing, but the single crystal as a sample to study the metal