Device and method for preparing aluminium oxide short staple preform

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...

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, so the transformation of silica sol is not complete at this temperature, and the due bonding effect cannot be achieved, and the incomplete transformation of the binder remains in the preform, which affects the comprehensive performance of the composite material. adversely affect

The most important thing is that during the impregnation process, silica sol acts as a binder to react with Al, Mg, etc. in the alloy to form brittle MgO crystals and when the amount of Si-Mg phase is large enough, it will have an adverse effect on the comprehensive performance of the composite material; Three is Al 2 o 3 The drying time of fibers and preforms is as long as 30-40 hours. The preform manufacturing cycle is too long. At the same time, too long baking time will easily lead to cracking of the preform and even fiber shedding. It will also cause the binder to segregate around the preform, making sintering The central strength of the prefabricated body is low

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