| HUANG Shao-feng,GAN Zhi-wei,HU Ning-fei,LU Jing,LI Dong-xu.Preparation and Properties of Core-shell SiC@Ti(C,N) Composites[J],52(4):410-416, 426 |
| Preparation and Properties of Core-shell SiC@Ti(C,N) Composites |
| |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2023.04.037 |
| KeyWord:SiC ceramic Ti(C,N) fracture toughness core-shell structure microhardness toughening mechanism |
| Author | Institution |
| HUANG Shao-feng |
College of Materials Science and Engineering,Fujian Xiamen , China ;Institute of Manufacturing Engineering, Huaqiao University, Fujian Xiamen , China |
| GAN Zhi-wei |
College of Materials Science and Engineering,Fujian Xiamen , China |
| HU Ning-fei |
College of Materials Science and Engineering,Fujian Xiamen , China |
| LU Jing |
Institute of Manufacturing Engineering, Huaqiao University, Fujian Xiamen , China |
| LI Dong-xu |
College of Materials Science and Engineering,Fujian Xiamen , China |
|
| Hits: |
| Download times: |
| Abstract: |
| Carbide ceramic materials present widely applications in fine polishing and cutting industries due to their excellent mechanical properties. The preparation of carbide composite materials with specific structure will improve the comprehensive properties of materials. SiC@Ti(C,N) composites with core-shell structure were prepared by chemically coating nano-Ti(C,N) on the surface of 10 micron SiC and press-free sintering at low temperature in a tubular furnace. XRD, SEM, TEM and EDS were used to study the effects of annealing temperature and raw material ratio on the composition and microstructure of composite materials. The difference of oxidation resistance between single-phase and composite materials was compared by thermal analysis. The variation trend and reason of mechanical properties of composite materials were tested by micro-Vickers hardness tester and universal material testing machine. A model of core-shell partical densification was built to discussed the densification and toughened mechanisms of SiC@Ti(C,N) composites. The composition and microstructure of the composites are the core-shell structure of thin sheet Ti(C,N) coated SiC particles, which improves the oxidation resistance of the composites. As the sintering temperature increases, its microhardness increases firstly and then decrease. With the mass ratio of SiC/Ti(C,N) as a variable, the experimental results show that as the proportion of SiC increases, the microhardness, compressive strength and fracture toughness increase firstly and then decrease, the microhardness of SiC@Ti(C,N) composites prepared under the optimal experimental conditions surpasses that of SiC. The results show that the SiC@Ti(C,N) composites with raw material ratio of 11∶1 fabricated at 1 250 ℃ have maxium microhardness, compressive strength and fracture toughness, which are 3 273HV, 434 MPa and 4.38 MPa.m1/2 respectively. The properties of SiC@Ti(C,N) composites with core-shell structure are improved by comparing the mechanical properties of composites and single carbide materials. The densification mechanism of this composites is the pore in the composites was filled by nano Ti(C,N) and densification of SiC was promoted, which helps the formation of Ti(C,N) framework and toughen composites by its crack deflection. Before sintering, there are still more pores between the particles in the composite, resulting in low density. As the calcination temperature rises above 1 200 ℃, favorable conditions are provided for the energy release of Ti(C,N) atoms, which promotes the migration of powders. Meanwhile, nano-Ti (C,N) grains grow up and dissolve with each other, which increases the contact area between powders, gradually diffuses into the pores and fills them, resulting in the decrease of pores. At the same time, SiC particles were pushed to shrink to densification. The main function of Ti(C,N) with low modulus is to deflect crack and toughen the composite. After cooling, a stress field is generated at the interface of grain boundary of the two phases, resulting in weak interfacial bonding. When the crack expands to the interface, the crack will extend along the weak interfacial bonding and deflect. When the crack propagates inside the material, the crack will extend along the Ti(C,N) skeleton bending, which makes the crack propagation path become tortuous and the propagation resistance is greatly increased, thus greatly reducing the possibility of the internal SiC particles directly fracture to form a long straight crack. |
| Close |
|
|
|