Titanium and titanium alloys have low modulus of elasticity, corrosion resistance, and excellent bio- and mechanical compatibility, and are widely used in surgical implants. In recent years, there have been many reports on medical titanium alloys. The product specifications are mainly plate and bar, which are used for surgical trauma bone plates and fixation screws, which is very effective for the fixation of fracture blocks. For short-fracture or avulsion fractures and other stress-fixed fracture fixation, the Kirschner wire made of filaments is generally 0.8-2.5 mm in diameter. Ti-6Al-4V titanium alloy is an ideal surgical implant material due to its excellent mechanical properties such as high strength and high toughness. In order to achieve a good fixed connection, the material must have high tensile strength and good plasticity and bending properties. The conventional method uses cold drawn stainless steel wire, but the material is poorly plastic, the elongation is less than 5%, and the bending property is poor. In this paper, Ti-6Al-4V titanium alloy was used to prepare ultra-high strength Ti-6Al-4V titanium alloy straight wire by means of reasonable regulation of interstitial elemental oxygen in the alloy, and hot drawing of rolled billet. The effect of the content and process control on the mechanical properties of the material, in order to obtain the best preparation method.
Ti-6Al-4V titanium alloy adopts nominal distribution ratio, mixing, pressing electrode and re-melting by vacuum self-consumption to produce a series of Φ460mm ingots. The ingot is subjected to β single-phase heating forging and blanking to obtain a Φ220 mm×400 mm test forging blank. The final forging temperature of the blank forging is slightly lower than that of the general Ti-6Al-4V titanium alloy ingot, about 800 °C. The Φ220mm×400mm forging billet is heated and forged by α+β two-phase zone, and the large deformation temperature is controlled and rolled into Φ8mm billet; then the hole mold is controlled by temperature and hot drawing, and three kinds of titanium of Φ1mm, Φ2mm and Φ2.5mm are obtained. Alloy wire was used to analyze the effects of different materials and process parameters on the mechanical properties of Ti-6Al-4V titanium alloy wire. The Ti-6Al-4V titanium alloy was etched by an acid ratio of V (HF:HNO3:H2O) = 1:3:10. Through the large-deformation temperature-controlled hot rolling in the two-phase region, the grain of Ti-6Al-4V titanium alloy is refined, and the ultrafine grained wire is obtained by controlled temperature hot drawing, the crystal grain is about 0.5 μm; and with the oxygen in the alloy The increase of the content, the refinement of the drawing specifications, the mechanical properties of the wire material are improved, and the plasticity is decreased. The comprehensive comparison shows that the tensile strength and plasticity of the wire containing oxygen of 0.14wt% Ti-6Al-4V Φ2.0mm reach 1270MPa and 12 respectively. %, excellent mechanical properties, very suitable for medical K-wire products. Ultrafine grain Ti-6Al-4V wire exhibits ductile fracture along the equiaxed α phase grain boundary at room temperature. Ultrafine grain and high density dislocation are the fundamental reason for the material to obtain high strength.