Sun Haiyang,Ou Junfei,Cheng Liang,Sun Lingyan,Lu Yalin,Liu Wenchang
To improve the deformability of 6061Al–TiC composites, a laminated structure of 6061Al–TiC/6061Al was prepared by combining spark plasma sintering (SPS) and hot roll bonding. T6 treatment was applied to the roll-bonded 6061Al–TiC/6061Al laminated composites. Different contents of TiC nanoparticles were added into the inner 6061Al–TiC composite layers. The effect of the volume fraction of the TiC nanoparticles was revealed on the microstructure characterization, texture evolution and tensile properties. The recrystallization fraction and grain size of the 6061Al–TiC composite layers decreased with increasing TiC nanoparticle volume fraction. The texture in rolled 6061Al–TiC composite layers was characterized by weak Goss and β fiber. After T6 treatment, the texture in the 6061Al was cube component, while the recrystallized grains in the 6061Al–0.2TiC and 6061Al–0.5TiC composite layers exhibited cube and R components, respectively. The tensile strength of the 6061Al–TiC/6061Al laminated composites first increased with the volume fraction of TiC nanoparticles and then decreased when the TiC nanoparticles addition exceeded 0.5 vol%. Whereas, the elongation of the 6061Al–TiC/6061Al laminated composites decreased continuously with increasing the volume fraction of TiC nanoparticles. The ultimate strength and yield strength, respectively reached maximum values of 337 MPa and 316 MPa for the 6061Al–0.5TiC/6061Al laminated composites, and the elongation of the laminated composites was 21.6%. Graphical abstract
Zihan Wang,Qianglong He,Shifeng Ren,Aiyang Wang,Weimin Wang
B 4 C–TiB 2 –graphite ceramic composites were fabricated via reactive hot pressing using B 4 C and TiC as the raw materials. With an increase in the TiC content, the grain size of B 4 C decreased continuously because B 4 C grain growth was inhibited by the TiB 2 and C reaction products. However, excessive TiC content caused an increase in TiB 2 and graphite grain size and the formation of TiB 2 –graphite agglomerates. When the composition of the ceramic composite was 95.1 wt%B 4 C–3.9 wt%TiB 2 –1.0 wt%graphite, the Vickers hardness and bending strength was optimized at 34.9 GPa and 688 MPa, respectively. The results showed that crack deflection is the main toughening mechanism of B 4 C–TiB 2 –graphite ceramic composites, and the effect of TiB 2 –graphite on crack propagation is particularly significant. When the composition of the ceramic composite was 75.6 wt%B 4 C–19.4 wt%TiB 2 –5.0 wt%graphite, the fracture toughness was optimized at 6.77 MPa·m 1/2 . These results provide guidelines on how to effectively control the combined properties of B 4 C–TiB 2 –graphite ceramic composites in future investigations.
Al 2 O 3 -ZrO 2 -TiC composites with different proportions of TiC were prepared by ball milling and spark plasma sintering. Structural characterization revealed that the composites exhibited fine and homogeneous microstructures. No other phases except α-Al 2 O 3 , t-ZrO 2 and c-TiC were detected by XRD in all Al 2 O 3 -ZrO 2 -TiC composites. The internal stress induced by the mismatch of the thermal expansion coefficients result in a shift of t-ZrO 2 diffraction peak. SEM and TEM observations showed that the Al 2 O 3 grain size was inversely proportional to the TiC content, while the grain sizes of ZrO 2 and TiC stayed nearly constant. HRTEM micrograph presented that there are glassy phase boundaries with thickness of several nanometers around the TiC grains. As the TiC content increases, the relative density and hardness decreased from 99.2 to 97.7 pct and from 21.0 to 15.8 GPa, respectively. Compared with Al 2 O 3 -ZrO 2 matrix, composites with TiC exhibited lower flexural strength but enhanced fracture toughness. Composite with TiC of 10 vol pct possessed the best friction property. The increased porosity was mainly responsible for the deterioration of mechanical and friction properties except for the fracture toughness. The improvement in fracture toughness with increasing TiC content was attribute to the crack deflection and pinning effects induced by the TiC particles.
危险品化学品经营许可证（带存储）