EBSPによるゴムメタルの変形組織解析

抄録

  EBSP (electron backscattering pattern) analysis was performed on microstructure of three β titanium alloy specimens after cold working to study peculiar plastic behavior of the multifunctional alloy, Gum Metal. The specimens employed were Ti-36%Nb-2%Ta-3%Zr-0.3%O (mass%) alloy (Gum Metal) and two reference alloys having lower and higher bcc phase stability than that of Gum Metal. Deformation twinning of {332} <113> was observed in the specimen with lower bcc stability, and dislocation glide in the specimen with higher bcc stability. Orientation boundaries with rotation angle of 10-30 degrees were observed in Gum Metal specimen, and they are considered to be identical to the giant planar faults which were observed in TEM in the previous study. It seems that the giant faults act as grain boundaries and numerous subgrains are generated in the later stage of plastic deformation. Amount of crystallographic rotation in deformed Gum Metal specimens was very large, which implies that huge elastic energy was stored during plastic deformation.