CN1396290A

CN1396290A - Process for preparing Ti-base composition by self reaction and powder metallurgy

Info

Publication number: CN1396290A
Application number: CN 02112260
Authority: CN
Inventors: 吕维洁; 覃业霞; 杨志峰; 张荻
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2002-06-27
Filing date: 2002-06-27
Publication date: 2003-02-12
Anticipated expiration: 2022-06-27
Also published as: CN1151299C

Abstract

A process for preparing the Ti-base composite material by self-reaction and powder metallurgy includes such steps as proportioning spongy titanium, boron carbide, graphite powder and alloy element power, then mixing, die pressing, and vacuum sintering at 1200-1400 deg.C for 2-18 hr, and cooling.

Description

Self-reaction-powder metallurgy preparation method of titanium-based composite material

The technical field is as follows: the invention relates to a self-reaction-powder metallurgy preparation method, in particular to a self-reaction-powder metallurgy preparation method of a titanium-based composite material, belonging to the field of composite materials.

Background art: titanium and its alloy have melting point high, non-magnetic, thermal expansion coefficient low, specific strength and specific stiffness high, and corrosion resistance good, resist many excellent characteristics such as the biological erosion, therefore apply to fields such as aviation, spaceflight, traffic, chemical industry, petroleum, shipbuilding, textile, papermaking, energy, biomedicine extensively. However, with the development of technology, the traditional titanium alloy material reaches the limit of the performance thereof and cannot meet the increasingly strict requirements on comprehensive performance, so that the trend of transferring from solid solution strengthening titanium alloy to ordered intermetallic compounds and titanium-based composite materials appears. In order to compete for the technical and market advantages of titanium materials, development and research of titanium alloy composite materials are carried out in various countries in the world. Compared with the continuous fiber reinforced titanium-based composite material with high price, complex process and anisotropic material, the particle reinforced titanium-based composite material with isotropy and easy processing has great improvement range of mechanical property, relatively reduced cost and obvious technical and economic benefits, thereby causing wide attention of people. Researchers in various countries around the world have developed and designed various different processing techniques to prepare particle-reinforced titanium-based composites. Although the performance of the compositeis significantly improved compared to the matrix titanium alloy, the cost of the composite is also significantly increased, thereby limiting the application of the titanium matrix composite. For example, after the titanium-based composite material is used in the automobile industry, the weight of an automobile can be greatly reduced, the fuel consumption of the automobile can be reduced, the working efficiency of the automobile can be improved, the environment can be improved, the noise can be reduced, and the like, but the currently prepared titanium-based composite material is too high in cost and only can be applied to racing cars and high-grade cars. Therefore, in addition to exerting its own performance advantages, titanium-based composites are required to enter the automotive market at a further cost reduction to levels acceptable to the automotive industry. The countries such as the United states, the Japan and the Russia are actively searching for methods and processes for reducing the cost, and work is mainly carried out on the following two aspects, namely, the development of a low-cost alloy system and the improvement of a production process. Because the powder metallurgy process has the characteristic of near net shape, the required parts can be prepared simply and conveniently at low cost, thereby obtaining the favor of people. Document search revealed that StanleyAbkowitz et al, Industrial Heating, 1993,60 (9): 32-37, written "Particulate repaired titanium alloys compounded and Particulate reinforced titanium alloy composites produced simply by using cold and hot isostatic pressing" introduced that the CermeTi series titanium-based composites developed by Dynamet technology company in the United states have been commercially used in the fields of automobile industry and the like, and are the earliest titanium-based composites produced industrially in the world. However, the compounding method adopted by the company is to artificially add reinforcing particles such as TiC into the titanium alloy andprepare the titanium alloy by an external addition method, so that the problems of uniform distribution of the reinforcing bodies, complete combination of the reinforcing bodies and a matrix and the like cannot be fundamentally solved, and the performance of the composite material can be reduced by the pollution of the external reinforcing bodies.

Summary of the invention and detailed description: the invention provides a self-reaction-powder metallurgy preparation method of a titanium-based composite material, aiming at the defects and defects of the prior art, the method organically combines the traditional powder metallurgy technology with the in-situ synthesis technology, prepares the titanium-based composite material with different molar ratios of TiB whiskers and TiC particles mixed and enhanced by utilizing the chemical reaction among titanium, boron carbide and graphite, effectively solves the problems of high cost and additional reinforcement pollution of the traditional composite material, ensures that the reinforcement is more uniformly distributed and better combined with a matrix, can prepare the novel titanium-based composite material and parts thereof simply and conveniently at low cost, is suitable for large-batch industrial production, and is particularly suitable for processing parts on a large scale, thereby meeting the urgent requirements on low-cost preparation technology and high-performance titanium material. The method comprises the following steps:

(1) weighing proper stoichiometric titanium sponge (titanium powder), boron carbide, graphite powder and alloying element powder;

(2) the powder is uniformly mixed by a mixing method such as a V-shaped mixer, a ball mill and the like, and a known mixing method is adopted, so that mixed powder with various uniformly distributed powder particles can be obtained without special measures;

(3) then preparing a green body with a preset shape from the mixed powder obtained in the mixing step by adopting methods such as compression molding, cold isostatic pressing and the like;

(4) sintering the prepared green body in a vacuum sintering furnace with the vacuum degree controlled at 1 × 10^-1Pa-1×10^-3Pa, the sintering temperature is controlled between 1200 ℃ and 1400 ℃, and the sintering time is 2 to 18 hours;

(5) finally, cooling along with the furnace to prepare the in-situ synthesized titanium-based composite material.

The following further limitations of the process of the present invention are: the powder materials are mixed by one or both of the following two reaction schemes:

the volume fraction of the reinforcement is controlled within 30 percent, the alloying elements comprise one or more of all traditional titanium alloying elements such as Al, Sn, Zr, Mo and the like, the content of the alloying elements is adjusted according to the required performance requirement, the proportion of the alloying elements is adjusted, and the molar ratio of the TiB to the TiC of the reinforcement can be realized by adding different boron carbide and graphite powder.

The titanium-based composite material prepared by the method is prepared and formed by secondary processing techniques such as hot forging, hot rolling and the like, and the required part consisting of the titanium-based composite material is prepared by near-net forming by a compression molding method.

The invention has substantive characteristics andremarkable progress, prepares the high-performance titanium-based composite material simply and at low cost under the condition of not changing the traditional powder metallurgy preparation equipment and process flow, and can prepare the composite materials with different performances by adjusting different reinforcement contents, reinforcement molar ratios and matrix alloy components so as to meet different requirements. Compared with an ingot metallurgy process, the self-reaction-powder metallurgy process for preparing the TiB and TiC reinforced titanium-based composite materials with different molar ratios has the characteristic of near-net-shape forming, and is particularly suitable for preparing parts in batches.

The following three examples are provided in connection with the present disclosure:

examples1: 1% (TiB + TiC)/Ti composite material is prepared (TiB: TiC is 4: 1). Weighing 99.81% of sponge titanium and 0.19% of boron carbide powder according to the proportion, uniformly mixing the powder by a V-shaped mixer, and preparing a round green compact from the mixed powder obtained in the mixing step by a compression molding method. Sintering the prepared green body in a vacuum sintering furnace with the vacuum degree controlled at 1 × 10^-1Pa, the sintering temperature is 1200 ℃, the sintering time is 18 hours, and finally the in-situ autogenous titanium-based composite material is prepared by furnace cooling.

Example 2: 15% (TiB + TiC)/Ti composite material (TiB: TiC is 1: 1) is prepared. Weighing titanium powder (96.99%), boron carbide (1.75%) and graphite (1.26%) according to a ratio, uniformly mixing the powder by using a ball mill, preparing a rectangular green compact from the mixed powder obtained in the mixing step by using a cold isostatic pressing method, sintering the prepared green compact in a vacuum sintering furnace, and controlling the vacuum degree to be 1 x 10^-2Pa, the sintering temperature is 1300 ℃, the sintering time is 8 hours, and the in-situ autogenous titanium-based composite material is prepared by furnace cooling. Finally, the steel plate is rolled into a plate with specified size by a hot rolling process.

Example 3: 28% (TiB + TiC)/Ti-8% Al composite material (TiB: TiC is 4: 1) is prepared. Weighing titanium sponge (90.08%), boron carbide powder (5.17%) and aluminum powder (4.75%) according to a ratio, uniformly mixing the powders by a V-shaped mixer, preparing a round green body from the mixed powder obtained in the mixing step by a compression molding method, sintering the prepared green body in a vacuum sintering furnace, and controlling the vacuum degree to be 1 x 10^-3Pa, the sintering temperature is 1400 ℃, the sintering time is 2 hours, and finally the in-situ autogenous titanium-based composite material is prepared by furnace cooling.

Claims

1. A self-reaction-powder metallurgy preparation method of a titanium-based composite material is characterized by comprising the following steps: (1) weighing proper stoichiometric sponge titanium, boron carbide, graphite powder and alloying element powder; (2) mixing the above powders with V-shaped mixer and ball millMixing the powders uniformly; (3) then preparing a green body with a preset shape from the mixed powder obtained in the mixing step by adopting methods such as compression molding, cold isostatic pressing and the like; (4) sintering the prepared green body in a vacuum sintering furnace with the vacuum degree controlled at 1 × 10^-1Pa-1×10^-3Pa, the sintering temperature is controlled between 1200 ℃ and 1400 ℃, and the sintering time is 2 to 18 hours; (5) finally, cooling along with the furnace to prepare the in-situ synthesized titanium-basedcomposite material.

2. The process for the self-reactive-powder metallurgical preparation of titanium-based composites as claimed in claim 1, wherein the powder raw materials are mixed by reaction according to one or both of the following two reaction schemes: (x +5) ，。

3. The method of claim 1, wherein the volume fraction of reinforcement is controlled to be within 30%.