CN101786883A

CN101786883A - Functionally-gradient ceramic knife tool with layer-by-layer nested structure and preparation method thereof

Info

Publication number: CN101786883A
Application number: CN200910256570A
Authority: CN
Inventors: 刘战强; 万熠; 黄传真; 刘继刚
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2009-12-30
Filing date: 2009-12-30
Publication date: 2010-07-28
Anticipated expiration: 2029-12-30
Also published as: CN101786883B

Abstract

The invention discloses a functionally-gradient ceramic knife tool with a layer-by-layer nested structure and a preparation method thereof. The functionally-gradient ceramic knife tool at least comprises three layers of composites including AlMgB14 and TiB2; the three layers of composites are distributed layer by layer from inside to outside, and the mass ratios of the two materials in each layer are different; the content of the AlMgB14 is gradually increased from a core part layer to a surface layer; the content of the AlMgB14 is the lowest at the core part layers and the highest at the surface layers of a front knife surface, a main rear knife surface and an auxiliary rear knife surface of the ceramic knife tool. In the preparation method, at least three types of composite powder with different mass ratios of the AlMgB14 and the TiB2 are prepared; each type of composite powder is vacuum-dried and screened, then spread and pre-pressed in a graphite mould layer by layer from inside to outside according to the content of the AlMgB14 from low to high, and is finally sintered in a vacuum hot-pressing manner. As the layer-by-layer nested structure is adopted in the invention, mechanical performance indexes of the ceramic knife tool are increased and the service life of the ceramic knife tool is prolonged by 20 to 30% than that of the functionally-gradient ceramic knife tool with a traditional structure.

Description

A kind of functionally-gradient ceramic knife tool with layer-by-layer nested structure and preparation method thereof

Technical field

The present invention relates to a kind of FUNCTIONALLY GRADED CERAMIC TOOL and preparation method thereof, belong to the ceramic cutting tool material technical field,

Background technology

AlMgB ₁₄It is a kind of novel super-hard wear-resistant boride, characteristics with high rigidity, low-friction coefficient, have advantages such as high hardness, wear resistance, thermotolerance and chemical stability with its sintex that is matrix prepares, be suitable for machining titanium alloy, yet the fragility of itself has limited its range of application, and its intensity is also lower.Researchist and cutter manufacturer generally adopt to AlMgB both at home and abroad ₁₄The method of adding toughened and strengthened phase in the matrix improves its mechanical property, as adding AlN, TiC, TiB ₂Deng, wherein add TiB ₂Toughened and reinforced effect best.Yet the effect of these toughened and strengthened methods is limited, still can not satisfy the requirement of high-efficient cutting difficult processing work material such as titanium alloy etc.Function-graded material is a kind of component and the equal continually varying advanced composite material of performance that grows up the middle and later periods 1980s, has the function of excellent heat insulation, solar heat protection and mitigation thermal stresses.Earlier 2000s, gradient function ceramic applications make cutter have interior tough outer hard characteristic in cutting tool.Yet, present FUNCTIONALLY GRADED CERAMIC TOOL as shown in Figure 1, be sandwiched type structure, three layers or more multi-layered being superimposed, there is following shortcoming in this structure: in cutting, it is downwards the gradient function structure that the point of a knife place has only along rake face, does not then possess the gradient function structure along main back knife face and minor flank to the cutter core, makes the point of a knife place that is made of rake face, master's back knife face and minor flank still easily produce tipping.

Summary of the invention

The present invention is directed to the deficiencies such as easy generation tipping of the FUNCTIONALLY GRADED CERAMIC TOOL existence of existing sandwiched type structure, provide a kind of reliability higher, resistance to wear, resisting breakage, be difficult for the FUNCTIONALLY GRADED CERAMIC TOOL of tipping, a kind of preparation method of this FUNCTIONALLY GRADED CERAMIC TOOL is provided simultaneously.

Functionally-gradient ceramic knife tool with layer-by-layer nested structure of the present invention is by the following technical solutions:

This FUNCTIONALLY GRADED CERAMIC TOOL comprises three layers of AlMgB at least ₁₄And TiB ₂The mixture of two kinds of materials, each layer mixture successively distribute from inside to outside, and the mass ratio of two kinds of materials is all different in each layer, by core layer AlMgB to all directions on top layer ₁₄Content increase gradually, the rake face of cutter, main back knife face and minor flank all are AlMgB of core layer ₁₄Content is minimum, and the AlMgB on top layer ₁₄Content is the highest.

The preparation method of above-mentioned functionally-gradient ceramic knife tool with layer-by-layer nested structure may further comprise the steps:

At first adopt wet processing to disperse batch mixing, prepare the AlMgB of at least three kinds of different mass ratios ₁₄And TiB ₂Composite powder, then every kind of composite powder is carried out vacuum-drying and crosses 180 mesh sieves, according to AlMgB ₁₄Content order from low to high in graphite jig, carry out powder successively sprawling from inside to outside (every layer bed thickness and composite powder quality are determined according to the material and the complete processing optimization of workpiece to be processed) and precompressed; Adopt vacuum heating-press sintering at last.

The hot pressed sintering pressure of vacuum heating-press sintering is that 100Mpa～110Mpa, sintering range are that 1400 ℃～1500 ℃, soaking time are 60 minutes.

The present invention is owing to adopt the nesting structure that successively distributes from inside to outside more than three layers, make rake face, the master back knife face of cutter consistent with minor flank structure and material content, be gradient-structure along point of a knife to cutter core all directions, strengthened every mechanical performance index of sintex, surperficial average hardness is reached about 36Gpa, and fracture toughness reaches

About, all be higher than the conventional ceramic cutter material of same material system and the FUNCTIONALLY GRADED CERAMIC TOOL of traditional sandwiched type structure, be suitable for machining titanium alloy Ti-6Al-4V, especially under the high speed cutting condition, cutter life improves 20～30% than traditional structure FUNCTIONALLY GRADED CERAMIC TOOL, and cost is suitable with it; Production efficiency than inserted tool improves 80～120%, and surface quality improves a grade.

Description of drawings

Fig. 1 is the structural representation of the FUNCTIONALLY GRADED CERAMIC TOOL of existing sandwiched type structure.

Fig. 2 is the structural representation of square (comprising rhombus) FUNCTIONALLY GRADED CERAMIC TOOL of preparing of the present invention.

Fig. 3 is the structural representation of the cylindrical FUNCTIONALLY GRADED CERAMIC TOOL for preparing of the present invention.

Embodiment

The method of the FUNCTIONALLY GRADED CERAMIC TOOL that is used for the High Speed Machining titanium alloy material with the preparation three-decker elaborates to the present invention below.This preparation method who is used for the three-decker FUNCTIONALLY GRADED CERAMIC TOOL of machining titanium alloy material may further comprise the steps:

(1) adopts the wet processing batch mixing, with AlMgB ₁₄And TiB ₂The composite powder of three kinds of different blended composition and division in a proportion of two kinds of material preparations, AlMgB ₁₄And TiB ₂Mass percent be respectively 60: 40,65: 35 and 70: 30, the numbering of these three kinds of composite powders is respectively A, B, C, vacuum-drying then, crosses 180 mesh sieves.

(2) took by weighing composite powder A, B, C in 36.4: 26.5: 37.1 by mass percentage respectively.

(3) composite powder that takes by weighing is carried out powder by A, B, C order in graphite jig lamination is filled (successively outwards being filled along rake face, main back knife face and minor flank by the cutter core) and precompressed.Can make square (comprising rhombus) cutter shown in Figure 2 (material composition from inside to outside along each to Gradient distribution), also can be made into cylindrical cutting tool shown in Figure 3 (each composition of layer distributes with radial gradient from inside to outside vertically).

(4) under 1400 ℃～1500 ℃ sintering temperature and 107MPa pressure, carry out hot pressed sintering, and carry out vacuum protection, be incubated 60 minutes, then furnace cooling.The cutter that obtains is axially and multilayered structure radially, and various compositions are from down to up, transition from inside to outside, AlMgB ₁₄Content simultaneously from the bottom to the top layer, from the internal layer to the skin, successively increase the AlMgB of central position ₁₄Content is minimum, and the AlMgB on surface ₁₄Content is the highest.

Also can obtain the FUNCTIONALLY GRADED CERAMIC TOOL of more multi-layered nesting structure from inside to outside according to the method described above, or make and reach radially all FUNCTIONALLY GRADED CERAMIC TOOL of symmetrical structure up and down.

Claims

1. a functionally-gradient ceramic knife tool with layer-by-layer nested structure comprises three layers of AlMgB at least ₁₄And TiB ₂The mixture of two kinds of materials is characterized in that: each layer mixture successively distributes from inside to outside, and the mass ratio of two kinds of materials is all different in each layer, by core layer to top layer AlMgB ₁₄Content increase gradually, the rake face of cutter, main back knife face and minor flank all are AlMgB of core layer ₁₄Content is minimum, and the AlMgB on top layer ₁₄Content is the highest.

2. functionally-gradient ceramic knife tool with layer-by-layer nested structure according to claim 1 is characterized in that: described every layer bed thickness and composite powder quality are determined according to the material and the complete processing optimization of workpiece to be processed.

3. the preparation method of the described functionally-gradient ceramic knife tool with layer-by-layer nested structure of claim 1 is characterized in that: may further comprise the steps:

At first adopt wet processing to disperse batch mixing, prepare the AlMgB of at least three kinds of different mass ratios ₁₄And TiB ₂Composite powder, then every kind of composite powder is carried out vacuum-drying and crosses 180 mesh sieves, according to AlMgB ₁₄Content order from low to high in graphite jig, carry out powder successively sprawling and precompressed from inside to outside; Adopt vacuum heating-press sintering at last.

4. according to the preparation method of the described functionally-gradient ceramic knife tool with layer-by-layer nested structure of claim 3, it is characterized in that: the hot pressed sintering pressure of described vacuum heating-press sintering is that 100Mpa-110Mpa, sintering range are that 1400 ℃～1500 ℃, soaking time are 60 minutes.