Study of the Structure and Mechanical Properties of Ti-38Zr-11Nb Alloy

Hip joint implants are one of the most common types of medical implants used to replace a damaged joint and restore its functional activity. Hundreds of thousands of surgeries are performed annually to install them, which underscores the importance of developing and improving materials for such implants. Modern materials for implants, including co-balt-chromium alloys, stainless steel, titanium and other titanium alloys, face problems such as the toxicity of certain elements (for example, aluminum, vanadium, nickel) and excessive Young's modulus, which negatively affects biomechanical compatibility. A mismatch between the stiffness of the implant material and the bone tissue, called stress shielding, can lead to bone resorption and loosening of the implant. Recent studies have shifted the focus to β-titanium alloys due to their exceptional biocompatibility, corrosion resistance, and low Young's modulus, which is close to the Young's modulus of bone tis-sue (10-30 GPa). Among them, Ti-38Zr-11Nb alloy is promising for use as an implant material. In this study, the microstructure, mechanical properties, and phase stability of Ti-38Zr-11Nb alloy were studied. Energy dispersion spectrometry confirmed the homo-geneous distribution of Ti, Zr, and Nb in the alloy. Microstructural analysis revealed elongated β-grains after rolling and quenching, and grinding contributed to recrystalliza-tion and the formation of subgrains. X-ray diffraction analysis confirmed the presence of a stable β-phase under any heat treatment conditions, which is explained by the use of Nb as a β-stabilizer and Zr as a neutral element with a weak β-stabilizing effect in the pres-ence of other β-stabilizers. The modulus of elasticity after annealing decreased from 85 GPa to 81 GPa. Mechanical tests showed a significant increase in tensile strength (from 529 MPa to 628 MPa) simultaneously with a 32% decrease in elongation to fracture of the samples. These changes are caused by microstructural transformations such as the for-mation of subgrains and rearrangement of dislocations. Based on the results of the study, it can be concluded that Ti-38Zr-11Nb alloy is a promising material due to its lower low Young's modulus relative to the classical materials used and stable β-phase, which pro-vides the possibility of long-term use of the implant, without the risk of formation of brittle phases.