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Ceramic forging method

A ceramic and forging temperature technology, applied in the field of ceramic forging, can solve the problems of low strain rate, high temperature, ceramic material dislocation and movement difficulties

Pending Publication Date: 2021-11-16
ZHENGZHOU UNIVERSITY OF AERONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Ceramic materials are mostly bonded by ionic bonds and covalent bonds, which makes it difficult to generate and move dislocations in ceramic materials.
Although the stress required to produce deformation will gradually decrease with the increase of atomic activity at high temperature, but high temperature and pressure are still required to achieve ceramic forging
Under the existing static pressure conditions, the high-temperature creep mechanism of ceramic materials is mainly based on Coble and Naborro-Herring diffusion mechanisms, with small strain and low strain rate. If the deformation mechanism is to be improved to slip or dislocation control In order to achieve the effect of increasing the strain amount and strain rate by the power-law deformation mechanism, very high temperature and very high static pressure are required, which often exceed the tolerance range of equipment and high-temperature molds such as graphite molds
This makes ceramic forging difficult or extremely costly

Method used

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  • Ceramic forging method

Examples

Experimental program
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Effect test

Embodiment 1

[0023] The ceramic forging method of the present embodiment uses hot-pressed sintered boron carbide ceramics (a cylinder with a diameter of 30 mm and a height of 4.61 mm and a relative density of 98%) added without sintering aids as ceramics to be forged, comprising the following steps:

[0024] Put the ceramics to be forged into a graphite mold with a diameter of 40mm, put the graphite mold filled with the ceramics to be forged into a high-temperature furnace, heat it to the forging temperature of 1900°C under vacuum conditions and keep it warm for 1 hour, and apply oscillating pressure during the holding stage, and the oscillating pressure waveform It is a sine wave, the frequency is 5Hz, the median pressure is 70MPa, and the amplitude is 10MPa. After oscillating forging for 1 hour, a boron carbide forging with a diameter of 40mm and a height of 2.78mm is obtained; the stress of the ceramic to be forged is deformed at 1900°C and 70MPa Index n = 3.38.

[0025] Gained ceramics...

Embodiment 2

[0027] The ceramic forging method of the present embodiment uses hot-pressed sintered boron carbide ceramics (a cylinder with a shape of 30 mm straight and a height of 5 mm and a relative density of 99.7%) added without sintering aids as ceramics to be forged, comprising the following steps:

[0028] Put the ceramics to be forged into a graphite mold with a diameter of 40 mm, put the graphite mold filled with the ceramics to be forged into a high-temperature furnace, heat to the forging temperature of 2000 ° C under vacuum conditions and keep it warm for 1 hour, and apply oscillating pressure during the holding stage, and the oscillating pressure waveform It is a sine wave, the frequency is 20Hz, the median pressure is 50MPa, and the amplitude is 10MPa. After oscillating forging for 1 hour, a boron carbide forging with a diameter of 40mm is obtained; the stress index n=3.63 when the ceramic to be forged is deformed at 2000°C and 50MPa .

[0029] The relative density of the obt...

Embodiment 3

[0031] The ceramic forging method of the present embodiment adopts adding mass ratio 10% Y 2 o 3 The silicon nitride ceramics (liquid-phase sintered silicon nitride ceramics with a relative density of 80%) as sintering aids are used as ceramics to be forged, comprising the following steps:

[0032] Put the ceramic to be forged into a graphite mold, heat it to 1800°C under a nitrogen atmosphere, and apply an oscillating pressure. The oscillation waveform of the oscillating pressure is a sine wave, the frequency is 5Hz, the median value of the oscillating pressure is 70MPa, and the amplitude is 10MPa. After oscillating forging for 1 hour, a deformed silicon nitride ceramic forging was obtained; the stress index n=2.2 of the ceramic to be forged at 1800° C. and 70 MPa.

[0033] The relative density of the obtained silicon nitride ceramic forging is 98%, the Vickers hardness is increased from 9GPa to 14GPa, and the bending strength is increased from 320MPa to 710MPa.

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Abstract

The invention relates to a ceramic forging method, and belongs to the technical field of ceramic preparation. The ceramic forging method comprises the following step that oscillating pressure is applied on to-be-forged ceramic at the forging temperature for forging. According to the ceramic forging method, the deformation mechanism of a ceramic material at the high temperature is changed under the oscillating pressure, the deformation capacity and the deformation rate of the ceramic material are improved, generation of micro fatigue in the ceramic material and the material deformation process are greatly improved, then the ceramic material can reach the higher deformation rate and the larger deformation amount at the lower temperature and pressure, and therefore ceramic forging can be achieved, and the cost is greatly reduced. In addition, through the deformation process generated by oscillating pressure forging, improvement of the relative density and strengthening of the performance of the ceramic material can be achieved, and forging forming of ceramic components in certain shapes and sizes can be achieved.

Description

technical field [0001] The invention relates to a ceramic forging method, which belongs to the technical field of ceramic preparation. Background technique [0002] Forging is a method of plastically deforming materials through pressure to obtain certain shapes, sizes and properties. Forging is often used in the processing and forming of metal materials. For ceramic materials, it is difficult to forge because of its difficulty in sliding and poor plasticity. The commonly used preparation method of high-performance ceramic components is mainly hot-press sintering. Compared with hot-press sintering, the forging process produces greater shear stress inside the material, causing greater deformation of the material, which can not only greatly eliminate the material The internal pore structure can also produce textured structure and work hardening to greatly improve the material performance. [0003] Ceramic materials are mostly combined by ionic bonds and covalent bonds, which ...

Claims

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Application Information

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IPC IPC(8): B28D1/00B28D7/00
CPCB28D1/00B28D7/00C04B35/563C04B2235/96C04B35/645C04B2235/95C04B2235/77C04B35/593C04B2235/3225C04B2235/3203C04B35/111C04B2235/6567B28B1/04B28B11/005C04B40/0259C04B2235/3821
Inventor 樊磊安立楠
Owner ZHENGZHOU UNIVERSITY OF AERONAUTICS
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