High strength high elasticity titanium alloy and preparation method

Abstract

The invention relates to a high strength high elasticity titanium alloy and a preparation method. The alloy comprises the following components in percentages by weight: 31-33wt% of Nb, 4-8wt% of Zr, 2-4wt% of Sn, 0.30-0.55wt% of O (0.3wt% endpoint value is not contained) and the balance of Ti. The preparation method of the alloy comprises the follow specific steps: adopting a vacuum nonconsumableelectric-arc furnace to smelt to obtain a uniform alloy ingot, performing solution treatment at 850-950 DEG C after hot forging of a rod, and performing water cooling to room temperature; then performing cold rolling deformation processing, wherein the deformation is 80-90%; and finally, performing ageing thermal treatment, wherein the heating temperature is 400-500 DEG C and the insulating time is 1-24h. The titanium alloy provided by the invention has high strength and relatively low elasticity modulus. The elastic deformability is superior to those of various beta-titanium alloys high in elasticity. The titanium alloy is quite suitable for preparing ultralight small-sized elastic parts in the fields of aerospace, machinery and the like, and also can be applied to preparing biomedical implants.

Description

technical field [0001] The invention relates to a high-strength and high-elasticity titanium alloy and a preparation method thereof, and belongs to the technical field of design and preparation of titanium alloy materials. Background technique [0002] Due to the high strength of titanium alloy, the elastic modulus and density are only 50% and 60% of steel, respectively, and the elastic deformation capacity is about twice that of steel, which is very suitable for use as a lightweight high-performance elastic material. β-titanium alloy has good formability and can be strengthened with age, making it an ideal choice for high-strength titanium alloy elastic materials. Since the 1980s, McDonnell Douglas, Lockheed, Boeing, Airbus and other aircraft manufacturing companies have gradually used β titanium alloy springs for the upper and lower locks of aircraft landing gear, door balance, hydraulic return and flight control. The representative titanium alloys for springs are Ti-15V-...

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Problems solved by technology

[0005] This type of medical titanium alloy also has the potential to be used as a high-performance elastic material after strengthening treatment, but there are still some problems: ① When the elastic modulus of the alloy in the solid solution state (composed of β phase) is reduced to 55GPa-65GPa, Its intensity also decreases synchronously (σ 0.2 Usually less than 700MPa), can not meet the requirements of high strength and high elasticity

②Through 80-90% cold rolling deformation of the solid solution alloy, the strength can be significantly increased and the elastic modulus can be reduced, but it will lead to high density of crystal defects, large residual stress, poor plasticity, low fatigue performance, and loss of use value

③By performing aging heat treatment at 400°C-500°C on the cold-rolled alloy, the strength and fatigue properties can be significantly improved, but due to the precipitation of a large amount of α-phase with high elastic modulus, the elastic modulus of the alloy usually increases to 80-90GPa, lead to σ 0.2 The / E value has no obvious advantage over elastic titanium alloys such as β-C and Timetal LCB mentioned above

After aging treatment at 400~600℃, the σ of the alloy 0.2 The / E value is high, up to 1.5%, but the strength is low (σ b 765~1030MPa, σ 0.2 is 634-775MPa), which cannot meet the comprehensive performance requirements of high-strength and high-elasticity titanium alloys

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