Evolution of microstructure, macrotexture and mechanical properties of high strength biomedical TA4 pure titanium during multi-pass ECAP

Abstract

The application of equal-channel angular pressing (ECAP) to TA4 pure titanium (Ti) results in a fine-grained microstructure. This technique presents an substitute for alloying, delivering enhanced mechanical properties without reducing biocompatibility and corrosion resistance. This study employs scanning electron microscopy (SEM), X-ray diffractometry (XRD), and transmission electron microscopy (TEM) to explore the microstructure evolution and the toughening mechanism of TA4 pure Ti after deformation. ECAP performed at 573 K endows TA4 pure Ti with a uniformly fine-grained microstructure, leading to a significant enhancement in its mechanical properties, exemplified by a yield strength of ∼731.9 ± 2.7 MPa and an elongation of ∼30.8± 1.3 %. While the {0001} basal slip primarily governs the ECAP deformation, the non-basal slip plays an increasingly important role with the increase of passes. The increase of yield strength can be attributed to grain refinement and the modification of the {0001} basal texture. Meanwhile, the improvement of plasticity is related to the strengthening of the {101‾ 0} prismatic texture. These findings offer fresh insights and methodologies for the design and manufacture of high-performance biomedical pure Ti.

Keywords

• Equal channel angular pressing
• Titanium
• Microstructural evolution
• Crystallographic texture
• Mechanical properties