The utility model relates to a powder metallurgy titanium alloy with high strength and plasticity and a processing method thereof, belonging to the titanium alloy field. In the processing method of the invention, the oxygen content of the ingot blank prepared by powder metallurgy method reaches 0.35wt %. The high oxygen content in the ingot blank will not only affect the design of the alloy forging temperature by increasing the alloy phase transition point, but also significantly increase the content of α stable elements in the alloy, thus affecting the mechanical properties and strengthening and toughening mechanism of the alloy. After three upsetting and three drawing forging, three upsetting and three drawing forging, bar rolling and annealing treatment, the high oxygen ingot billet has obtained a heterogeneous layered multistage second phase structure, which makes the alloy have good high strength and high plasticity matching. The high strength and high plasticity powder metallurgy titanium alloy of the invention has heterogeneous layered multistage second phase structure inside. The layered structure in the heterogeneous layered fine crystal structure can enhance the structural strength of the alloy, and the layered structure can accommodate the strain, so that the alloy can maintain high toughness and high plasticity.
Titanium alloy has the advantages of low density, high specific strength, good corrosion resistance and non-magnetic properties, and has been widely used in aviation, aerospace, ocean engineering and automotive industries. The near β titanium alloy has high specific strength and can effectively reduce the weight of the structure, so the application is gradually paid attention to.
The technical problems encountered in the development of near β high strength titanium alloy are increasing strength and decreasing plasticity. There are generally two ways to solve this technical problem. The first is to develop a new titanium alloy, strictly control the content of oxygen and other impurities, through complex forging process and high temperature solution aging heat treatment process, improve the strength and plasticity of alloy matching; Second, based on the existing high strength near β titanium alloy, the matching of strength and plasticity of the alloy is improved by changing the process path.
The powder metallurgy titanium alloy with high strength and high plasticity has heterogeneous layered multistage second phase structure inside. The layered structure in the heterogeneous layered fine crystal structure can enhance the structural strength of the alloy, and the layered structure can accommodate the strain, so that the alloy can maintain high toughness and high plasticity. The multistage second phase (including primary, secondary and tertiary phases) can enhance the strength of the alloy through multi-scale interface strengthening and high oxygen solution strengthening effect, and maintain good plasticity and toughness by improving the coordinated deformation capacity and deformation holding capacity of the alloy.
