EVOLUTION OF TEXTURE AND MICROSTRUCTURE DURING PROCESSING OF Ni_3Al BASED INTERMETALLIC ALLOYS

摘要

The cold rolling texture of Ni_3Al(B) or gamma' is different from that of f.c.c. metals and alloys of similar SFE, such as Ni. After low degree of deformation, the texture is basically pure metal type. The texture transforms to Brass type after heavy deformation. During cold rolling the LI_2 structure of gamma' transforms to DO_(22). The deformation of DO_(22) structure leads to twin formation which changes the texture from pure metal to alloy type. The DO_(22) structure of the cold rolled material reverts back to the initial L1_2 after annealing. During annealing the texture changes drastically even before the onset of recrystallization and becomes very weak, almost random. This can be correlated with the DO_(22)---L1_2 transformation. A weak recrystallization texture is produced from the already recovered and reordered material which itself has a weak texture. The prominent recrystallization texture components are {025}<100> and {011}<100>, instead of the cube {100} <001> which is the predominant component of the recrystallization texture of pure Ni.