Characteristics of Selected Properties of a Medical Titanium Alloy with Nb and Zr

This work characterized the metallurgical properties and selected mechanical properties of the medical alloy Ti13Nb13Zr. The study included an analysis of the hardness and fracture toughness of the medical material, which was first solution heat-treated and then aged. This work significantly complements the literature on this alloy. This supplementation involved selecting previously unused heat treatment parameters: solution heat treatment from 1050 °C and subsequent aging in the range of 350 to 550 °C. After solution heat treatment from 1050 °C and quenching in water, the alloy is characterized by a microstructure composed of titanium martensite (α′) with low hardness and high fracture toughness. The applied aging process, which involves diffusion phenomena, involved the decomposition of α′ martensite and the precipitation of new α and β phases, resulting in increased hardness and decreased fracture toughness. The use of a previously unused solution heat treatment temperature of 1050 °C may additionally improve mechanical properties, including hardness and fracture toughness (KIC), compared to lower solution heat treatment temperatures. The results obtained, using different heat treatment conditions, were confirmed by microstructural and phase analysis. This paper presents the characteristics of the tested alloy, a description of the heat treatment, and a detailed analysis of the phase transformations occurring during aging after solution heat treatment. Considerable attention was paid to fractographic analysis of fractures in samples obtained during fracture toughness tests. The obtained results significantly expand the knowledge of the tested alloy.