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Method for preparing closed-porosity TiAl-based porous thermal insulation material

A technology of thermal insulation materials and pores, which is applied in the field of preparation of porous thermal insulation TiAl alloy materials, and achieves the effects of simple preparation process, excellent thermal insulation performance and low cost.

Inactive Publication Date: 2014-02-19
GUANGZHOU RES INST OF NON FERROUS METALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

There are few reports on the research of TiAl-based porous thermal insulation materials

Method used

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  • Method for preparing closed-porosity TiAl-based porous thermal insulation material
  • Method for preparing closed-porosity TiAl-based porous thermal insulation material
  • Method for preparing closed-porosity TiAl-based porous thermal insulation material

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Experimental program
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Effect test

Embodiment 1

[0013] Mix Ti powder with a purity of 99.5%, 50 μm, and atomized spherical Al powder with a purity of 99.9%, 30 μm, at a molar ratio of 3:1. The mixed Ti / Al composite powder is cold-pressed at 800 MPa, and the billet is slowly heated to 620°C for sintering, kept for 4 hours, and then cooled. The vacuum degree during the entire sintering process is 5×10 -3 Pa. The compressive strength of the prepared porous thermal insulation material is 175MPa, the porosity is 58%, and the thermal conductivity is 4.02W / (m·K). figure 1 The metallographic microstructure photos show that the pores are basically closed pores that are not connected to each other, and the shape of the pores is relatively regular, the pore size distribution is uniform, and the pore size is small.

Embodiment 2

[0015] Mix Ti powder with a purity of 99.5%, 50 μm, and atomized spherical Al powder with a purity of 99.9%, 124 μm, in a molar ratio of 2:1. The mixed Ti / Al composite powder is cold-pressed at 800 MPa, and the billet is slowly heated to 620°C for sintering, kept for 4 hours, and then cooled. The vacuum degree during the entire sintering process is 5×10 -3 Pa. The compressive strength of the prepared porous thermal insulation material is 275MPa, the porosity is 60%, and the thermal conductivity is 3.3W / (m·K). figure 2 It can be seen from the metallographic microstructure photos that a small number of pores are connected together to form larger irregular connected pores.

Embodiment 3

[0017] Mix Ti powder with a purity of 99.5%, 50 μm, and atomized spherical Al powder with a purity of 99.9%, 300 μm, in a molar ratio of 1:1. The mixed Ti / Al composite powder is cold-pressed at 800 MPa, and the billet is slowly heated to 620°C for sintering, kept for 4 hours, and then cooled. The vacuum degree during the entire sintering process is 5×10 -3 Pa. The compressive strength of the prepared porous thermal insulation material is 127MPa, the porosity is 40%, and the thermal conductivity is 5.5W / (m·K). image 3 It can be seen from the metallographic microstructure photos that the pore diameter increases obviously, and the size distribution becomes uneven, but the pore sealing is better.

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Abstract

The invention relates to a method for preparing a closed-porosity TiAl-based porous thermal insulation material. The method is characterized by comprising the following steps: (1), mixing Ti powder with the purity being 99.5 percent and the particle size being 50 mu m with atomizing spherical Al powder with the purity being 99.9 percent and the particle size being 30-60 mu m according to the Ti: Al molar ratio being 3:1-1:2; (2), cold pressing the mixed powder under the pressure being 800 MPa to manufacture blanks; (3), sintering the cold-pressed blanks for 4 hours under the vacuum degree being 5*10-3Pa and the temperature being 620 DEG C to obtain the closed-porosity TiAl-based porous thermal insulation material. The porosity of the prepared TiAl-based porous thermal insulation material achieves 60 percents, the compression strength achieves 275 MPa, and the thermal conductivity achieves 3.3W / (m.K). The method has the advantages of simple preparation process and low cost and is beneficial to large-scale production.

Description

technical field [0001] The invention belongs to the field of intermetallic compounds, and in particular relates to a preparation method of a porous heat-insulating TiAl alloy material. Background technique [0002] The problem of heat protection is one of the biggest technical problems in the development of various aerospace vehicles. The metal reusable thermal protection system (TPS) can further reduce the structural mass, improve the durability, and reduce maintenance and repair costs. It is the first solution for the development of large-area TPS for aerospace vehicles today. As an emerging metal TPS material, the maximum service temperature of γ-TiAl alloy can reach 980 °C, but its density is less than half that of nickel-based superalloy, which also makes TiAl-based porous materials very attractive. [0003] The thermal conductivity of closed-pore porous thermal insulation materials is small, and the thermal conductivity of closed-cell foamed aluminum materials is only...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/08C22C21/00C22C14/00
Inventor 李达人韩胜利崔利群蔡一湘
Owner GUANGZHOU RES INST OF NON FERROUS METALS