Room temperature creep behavior of Ti–Nb–Ta–Zr–O alloy

• Nanoindentation was used to investigate room temperature creep behavior of gum metal.
• The creep stress exponent of gum metal is sensitive to the cold deformation history.
• The creep stress exponent of cold worked gum metal is approximately equal to 1.
• The creep of the cold-worked gum metal is governed by the shear deformation of giant faults.

The room temperature creep behavior and deformation mechanisms of a Ti–Nb–Ta–Zr–O alloy, which is also called “gum metal”, were investigated with the nanoindentation creep and conventional creep tests. The microstructure was observed with electron backscattered diffraction analysis (EBSD) and transmission electron microscopy (TEM). The results show that the creep stress exponent of the alloy is sensitive to cold deformation history of the alloy. The alloy which was cold swaged by 85% shows high creep resistance and the stress exponent is approximately equal to 1. Microstructural observation shows that creep process of the alloy without cold deformation is controlled by dislocation mechanism. The stress-induced α" martensitic phase transformation also occurs. The EBSD results show that the grain orientation changes after the creep tests, and thus, the creep of the cold-worked alloy is dominated by the shear deformation of giant faults without direct assistance from dislocations.