Device and method for preparing aluminium oxide short staple preform

A technology of aluminum oxide and short fibers, which is applied in the field of devices for preparing aluminum oxide short fiber preforms, can solve problems such as incomplete transformation of silica sol, delamination, and cracking of preforms, and shorten the preparation cycle and improve Preparation efficiency, rapid preparation effect

Inactive Publication Date: 2013-12-25
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The preparation of short fiber preforms mainly faces the following problems: one is the local agglomeration of short fibers; the other is that the volume fraction of the preform is unstable due to the rebound problem during wet preparation; the third is that the preform preparation cycle is too long and it is difficult to achieve Mass production and other issues
This process enables Al 2 o 3 The fibers are evenly dispersed, but there are the following problems: First, the pressure holding time of the preform is too short, only 15-20s, which may easily lead to defects such as cracking and delamination after the preform is taken out; second, the preform is dried in an oven at 150-200°C It is prone to problems such as binder segregation, preform delamination and cracking, or uneven drying process resulting in uneven strength distribution
In addition, the literature shows that the transformation temperature of silica sol is about 800 ° C, s

Method used

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  • Device and method for preparing aluminium oxide short staple preform

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0033] Method Example 2.

[0034] Step 1. Discontinuous Al 2 O 3sf Pretreatment and screening of short fibers.

[0035] (1) First, if you want to prepare a preform with a volume fraction of 25%, according to the weighing amount of Al 2 O 3 Short fiber, cut the continuous Al by hand 2 O 3 The fiber is cut into discontinuous Al with a length of 5mm 2 O 3 Fiber, this method can effectively eliminate discontinuous Al 2 O 3 The aggregation of short fibers into clusters.

[0036] (2) Use mechanical stirring device to disperse the agglomerated fibers in advance by inching mode. When the mixed slurry is more uniformly dispersed, then switch to low-speed stirring for 15 minutes to remove impurities suspended in the upper layer of the slurry and slag in the mixed slurry Ball to make it turbulent to facilitate Al 2 O 3 Subsequent processing of fibers. Use a filtering device to filter and remove, repeat 2 to 3 times as needed.

[0037] Step 2. Mix Al 2 O 3 The short fiber slurry is mechanicall...

Example Embodiment

[0048] Method Example 3.

[0049] Step 1. Discontinuous Al 2 O 3sf Pretreatment and screening of short fibers.

[0050] (1) First, if you want to prepare a preform with a volume fraction of 25%, according to the weighing amount of Al 2 O 3 Short fiber, cut the continuous Al by hand 2 O 3 The fiber is cut into discontinuous Al with a length of about 10mm 2 O 3 Fiber, this method can effectively eliminate discontinuous Al 2 O 3 The aggregation of short fibers into clusters.

[0051] (2) Use a mechanical stirring device to disperse the agglomerated fibers in advance by inching. When the mixed slurry is more uniformly dispersed, then switch to low-speed stirring for about 15 minutes to remove the impurities suspended in the upper layer of the slurry and the mixed slurry. Slag ball, make it form turbulent flow to facilitate Al 2 O 3 Subsequent processing of fibers. Use a filtering device to filter and remove, repeat 2 to 3 times as needed.

[0052] Step 2. Mix Al 2 O 3 The short fiber s...

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Abstract

The invention discloses a device and a method for preparing an aluminium oxide short staple preform to solve the technical problem of long preparation cycle of an existing method for preparing the aluminium oxide short staple preform. According to the technical scheme, a pressure cover (3) is provided with a pressure cover pore (2) and a porous mold is connected with an air breather through a quick connector. A bottom cover (9) is in a dual-layer structure, a plurality of micropores are distributed uniformly on the upper layer, a bottom cover pore (10) is arranged on the lower layer, and the bottom cover pore (10) is connected with a vacuum pump through the quick connector. A plurality of pressure head micropores (8) are distributed on a pressure head (7). An extrusion tank (5) is in thread connection with the pressure cover (3) and the bottom cover (9), the upper end of a vertical pressure lever (4) is fixedly connected with a horizontal pressure lever (1), and the lower end of the vertical pressure lever (4) passes through the pressure cover (3) and is then connected with the pressure head (7) through a bearing. Excess additive and water are removed through a vacuum pumping mode, so that cracking of the preform is effectively prevented, the process of preparing the preform quickly is implemented, and the preparation cycle is shortened.

Description

technical field [0001] The invention relates to a device for preparing aluminum oxide short fiber preform. It also relates to a method for preparing a short aluminum oxide fiber preform by using the device for preparing a short aluminum oxide fiber preform. Background technique [0002] Due to their high specific strength, specific stiffness, specific modulus, good electromagnetic shielding performance, good high temperature resistance, vibration absorption and designability, metal matrix composites have great potential in the fields of aerospace, weaponry and automotive electronics. Increasing application potential. When the vacuum pressure infiltration method is used to prepare short fiber reinforced metal matrix composites, the liquid matrix alloy is required to infiltrate into the pores of the preform skeleton under a pressure of 0.1-1 MPa, so the preform should have a certain high temperature strength. In addition, factors such as fiber aspect ratio, volume fraction a...

Claims

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Application Information

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IPC IPC(8): C22C47/06C22C101/04C22C121/00
Inventor 杨方张炳凤周计明齐乐华
Owner NORTHWESTERN POLYTECHNICAL UNIV
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