Preparation method of Ti3SiC2/SiC functionally gradient material

A functionally graded material and gradient technology, applied in the field of preparation of Ti3SiC2/SiC functionally graded materials, can solve problems such as difficult sintering and unbalanced sintering, and achieve good fracture toughness, reduced sintering temperature, and good thermal shock resistance.

Active Publication Date: 2016-05-04
XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY +1
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  • Abstract
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Problems solved by technology

SiC is much better than Ti 3 SiC 2 Difficult to sinter, resulting in unbalanced si...

Method used

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  • Preparation method of Ti3SiC2/SiC functionally gradient material
  • Preparation method of Ti3SiC2/SiC functionally gradient material
  • Preparation method of Ti3SiC2/SiC functionally gradient material

Examples

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preparation example Construction

[0051] Preparation Ti of the present invention 3 SiC 2 / SiC functionally graded material approaches include:

[0052] 1) Preparation of mixed powder

[0053] According to the composition of each gradient layer designed (see figure 1 ) to prepare the mixed powder. As SiC is difficult to sinter, the present invention selects β-SiC powder (particle size 2-4 μm) as the raw material of SiC phase, and introduces a small amount of nano-β-SiC powder (50-100nm), nano-β-SiC powder is both raw material and As a sintering aid, in order to improve the sintering effect of the gradient material of the present invention, Al+B+C composite sintering aid is introduced. The total amount of nano-SiC introduced in the entire gradient composite material is 18-20wt% of the total mass of SiC, and the amount of nano-SiC introduced in the gradient layer gradually increases according to the increase of its SiC phase content, and the SiC volume content does not exceed 40vol.%. The layer does not n...

Embodiment 1

[0089] 1)Ti 3 SiC 2 Gradient layer mixed powder preparation

[0090] Ti 3 SiC 2 According to the ratio of Ti:Si:Al:C 3:1.15:0.05:2, Ti (average particle size: 28μm, purity > 99.9%), Si (average particle size: 20μm, purity > 99.9%), C (average Particle size: 6 ~ 8μm, purity > 99.9%), mixed in the vibrating mill for 3 hours, the vibration frequency of the vibrating mill mixing is 25Hz, the amplitude is 8mm, the power is 1.2kw, SiC balls are used as grinding balls, and the grinding tank is lined The material is polyurethane, the shell material is stainless steel, and absolute ethanol is used as the medium.

[0091] 2) Preparation of SiC gradient layer mixed powder

[0092] The mixture was prepared in three proportions: 70wt.% micron SiC+30wt.% nanometer SiC, 80wt.% micron SiC+20wt.% nanometer SiC, 90wt.% micron SiC+10wt.% nanometer SiC. The average particle size of the micron SiC is 2-4 μm, and the purity is >99.9%, and the average particle size of the nano-SiC is 50-100 nm...

Embodiment 2

[0109] The difference between this example and Example 1 is that 5) the sintering temperature in the vacuum hot pressing sintering is 1700°C, the heat preservation is 5h, the maximum pressure is 25MPa, the pressure is started at 1100°C, and the pressure is appropriately reduced at about 1400°C; the sintering is good 15mm Ti 3 SiC 2 / SiCFGM sample has a density of 3.10g / cm 3 , the open porosity is 22%;

[0110] Design theoretical thickness (theoretical thickness of the final functionally graded material sample completely dense): 100vol.% Ti in the bottom layer 3 SiC 2 The designed theoretical thickness of the 100vol.% SiC powder layer of the powder layer and the top layer is 0.75mm, and the average thickness of each transition layer in the middle is 1.5mm. Calculate the volume of each layer according to the theoretical thickness and the inner diameter of the mold, calculate the theoretical density of each layer according to the weighted average in the compound law, and ...

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Abstract

The invention discloses a preparation method of a Ti3SiC2/SiC functionally gradient material, comprising the steps of mixing Ti3SiC2 powder and SiC powder in a die layer by layer in a gradient way, then preparing a blank, performing vacuum hot-pressing sintering on the blank to obtain a green body, and sequentially performing dipping densification and pyrolysis treatment on the green body; the SiC powder comprises micron beta-SiC powder and nanometer beta-SiC powder; the vacuum hot-pressing sintering temperature is 1600-1700 DEG C, and is kept for 3-5h, and the maximum pressure is 25MPa; the dipping densification comprises performing dipping densification on gradient layers containing 60-100 vol. percent of SiC in the green body subjected to the hot-pressing sintering in polycarbosilane liquid. The Ti3SiC2/SiC functionally gradient material prepared by the method is high in compactness, contains multiple gradient layers along the thickness direction from Ti3SiC2 to SiC (designing can be performed as required), the structure is uniform and compact in each gradient layer, interfaces among the gradient layers are moderately combined, the mechanical strength is high, the breaking tenacity is good, under high temperature, the oxidation resistance and the thermal shock resistance are good, and the Ti3SiC2/SiC functionally gradient material having 11 gradient layers and the thickness of 8-15mm can be prepared.

Description

technical field [0001] The invention belongs to the field of functional materials and relates to a Ti 3 SiC 2 / SiC functionally graded material (Functional Graded Material, FGM) preparation method, specifically a kind of improvement with Ti 3 SiC 2 Two materials with different thermomechanical properties, SiC and SiC, achieve a gradual compositional transition in the thickness direction to generate a densification method for FGM, realizing Ti 3 SiC 2 , Uniform densification of SiC two-phase materials. Background technique [0002] When two dissimilar materials are directly connected or compounded, the emergence of greater stress is a key factor that reduces the reliability of the material. Regardless of the composite material preparation process or the service process, the residual stress caused by temperature change is an important factor for composite material damage and destruction. At the two-phase interface of the composite material, the sharp change of the therma...

Claims

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Application Information

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IPC IPC(8): C04B35/56C04B35/575C04B35/645
CPCC04B35/5615C04B35/575C04B35/645C04B2235/75C04B2235/5436C04B2235/5454C04B2235/616C04B2235/65
Inventor 蔡艳芝尹洪峰王晓东蔚文绪马军强
Owner XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY
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