Novel powder metallurgy method for preparing nanometer or ultrafine structured titanium products

Abstract

The invention provides a novel powder metallurgy method for preparing nanometer or ultrafine microstructural titanium products. The method includes: step one, reducing grain size of titanium hydride powder to nanocrystalline level; step two, subjecting the titanium hydride powder in the nanocrystalline level to thermal consolidation to form pressed blanks; step three, under inert gas protection, heating the pressed blanks; step four, transferring the heated pressed blanks into an extruding device, and extruding under a certain pressure intensity and extrusion ratio to make the pressed blanks into the nanometer or ultrafine microstructural titanium products through an extruding mould with a certain inner cavity shape; step five, after extrusion is finished, cooling the extruded titanium products to the room temperature, and taking out; step six, heating the titanium products in a vacuum environment. A heating device used at the step three and the extruding device used at the step four are mounted in a same seal system, and insert gas is continuously fed into the seal system in a whole heating and extruding process.

Description

technical field [0001] The invention relates to a preparation method of titanium products, in particular to high-energy ball milling of titanium hydride powder to produce nanocrystalline titanium hydride powder, and adopting a thermomechanical consolidation process to dehydrogenate, consolidate and shape the powder to prepare high-strength titanium products The method belongs to the technical field of non-ferrous metal processing. Background technique [0002] As an important non-ferrous metal material, titanium and titanium alloys have been used in aerospace vehicles, ships and weapons in recent years due to their low density, high specific strength, corrosion resistance, high temperature mechanical properties, fatigue resistance and creep properties. It is widely used in the manufacture of military products. In addition, titanium also has great application potential in industries such as automobile, medical treatment, chemical industry, energy and daily consumption. Ther...

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Problems solved by technology

Usually these PCAs are some fatty acids, the main components are C, O and other elements. During the subsequent thermal processing, titanium is easy to interact with C and O, which are decomposed from PCA, which will affect the performance of the final product.

[0010] 2. Long grain refinement time

At present, it usually takes dozens of hours to refine the grains of coarse-grained pure titanium to the nanocrystalline level (<100nm) by high-energy ball milling, and the grain refinement efficiency is low.

[0011] 3. In the traditional thermal consolidation process, due to the slow heating / cooling speed, the fine grains after ball milling are easy to grow in high temperature environment, and the fine grain structure is difficult to be retained in the consolidated bulk sample

[0012] 4. Most of the existing methods of using titanium hydride as a raw material to prepare ultra-fine-grained titanium are to first dehydrogenate the ball-milled titanium hydride powder to form titanium powder, and then consolidate and form it through other subsequent processes. Due to dehydrogenation and consolidation The process is carried out in a high temperature environment, and titanium is easy to interact with impurity elements (such as C, O, H, etc.) in the environment in a high temperature environment, which affects the mechanical properties of the final sample. Zhongjun needs to strictly control the surrounding environment, and the production cost is relatively high

[0013] 5. Using titanium hydride to directly form titanium products, if the method of pressureless sintering is adopted, some pores will remain in the final material, and further densification treatment is required, such as extrusion, rolling, etc.; if pressure sintering is used, the It takes several hours to completely remove hydrogen from titanium, and the dehydrogenation efficiency is low

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