文章信息/Info

Title:

Study on the Preparation of B4C-SiC Composite Ceramics and Their Physical-Mechanical Properties

文章編號:

1674-3962(2022)05-0407-06

作者:

陳威1; 郝文慧1; 高東強1; 李秀青2

(1．陜西科技大學機電工程學院，陜西 西安 710021) （2．河南科技大學 金屬材料磨損控制與成型技術國家地方聯合工程研究中心，河南 洛陽 471000)

Author(s):

CHEN Wei1;  HAO Wenhui1;  GAO Dongqiang1;  LI Xiuqing2

(1.School of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi’an 710021, China) (2. National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials, Henan University of Science and Technology, Luoyang 471000, China)

關鍵詞:

B4C; SiC; 燒結壓力; 裂紋偏轉; 組織致密

Keywords:

B4C;  SiC;  sintering pressure;  crack deflection;  dense microstructure

分類號:

TQ174.1;TB332

DOI:

10.7502/j.issn.1674-3962.202012014

文獻標志碼:

A

摘要:

為提升B4C基陶瓷的力學性能，利用熱壓燒結工藝在不同壓力（30，35，40 MPa）下制備了B4C-20%SiC（質量分數）復合陶瓷試樣，并對其物理力學性能進行了研究。利用阿基米德排水法、壓痕法、三點彎曲法、單邊切口梁法測定復合陶瓷的密度、氣孔率、維氏硬度、彎曲強度以及斷裂韌性，同時利用掃描電子顯微鏡和X射線衍射儀分析并表征復合陶瓷的微觀組織、物相組成、斷口形貌等。研究結果表明， B4C-SiC復合陶瓷主要由B4C和SiC兩相組成，其微觀組織隨著燒結壓力的增大而變得更加致密；當燒結壓力由30增至40 MPa時，B4C-SiC復合陶瓷的密度由2.22增至2.64 g·cm-3，氣孔率由1.47%降至1.02%，維氏硬度由17.0升至32.6 GPa，彎曲強度由312.7提升至447.6 MPa，斷裂韌性由4.79增至7.21 MPa·m1/2。當燒結壓力達到40 MPa時，復合陶瓷斷裂過程中，發生裂紋偏轉，這種現象與致密的微觀組織以及B4C和SiC熱膨脹系數不匹配有關。

Abstract:

To improve the mechanical properties of B4C based ceramics, B4C-20wt%SiC composite ceramics were prepared by hot-pressing sintering under different pressures (30, 35 and 40 MPa), and the physical-mechanical properties of composite ceramics were studied. The Archimedes method, indentation method, three-point bending method and single edge notched beam (SENB) method were used to test the density, porosity, Vickers hardness, bending strength and fracture toughness of the composites. SEM and XRD methods were used to analyze the microstructure, phase composition and fractured morphologies of the B4C�睸iC composite ceramics. The results showed that the B4C-SiC composite ceramics were mainly composed of B4C phases and SiC phases, and their microstructure became denser with the increase of sintering pressure. When the sintering pressure increased from 30 to 40 MPa, the density of B4C-SiC composite ceramics increased from 2.22 to 2.64 g·cm-3, the porosity decreased from 1.47% to 1.02%, the Vickers hardness increased from 17.0 to 32.6 GPa, the bending strength increased from 312.7 to 447.6 MPa, and the fracture toughness increased from 4.79 to 7.21 MPa·m1/2. When the sintering pressure was 40 MPa, the crack deflection phenomenon was significantly observed on the fracture morphology of the composite, and the reason for this phenomenon may be related to the dense microstructure and the thermal expansion coefficient mismatch between B4C and SiC phases.