Thermal shock resistance of hot-pressed SiCw/Si3N4(w=whisker) composites was investigated by thermal shock resistance parameters and water quenching test. The results showed that the thermal shock resistance to fracture initiation and crack-stable repropagation deteriorated with increasing SiCw content in spite of the improvement of fracture toughness, K1C. This could be attributed to the great decrease of strength, σand the considerable increase of Young’s modulus, E, and thermal expansion coefficient, α,resulting from the addition of SiC whiskers. The curves of the residual strength, σ,after water quenching versus thermal shock temperature difference, △T, e.g. σ1-△T, showed good relationships with the calculated thermal stress fracture resistance parameter, R, and thermal stress crack stability parameter, Rst. The crack propagation of SiC whisker reinforced Si3N4 occurred primarily in a quasi-static manner, and it could be mainly attributable to SiC whiskers’ pulling-out and bridging toughening effects.

In situ TiB whiskers have a hexagonal shape in the transverse section and grow along the [010]TiB direction. The crystallographic planes of the TiB whiskers in the transverse section are always (100), (101) and (101). The stacking faults in TiB are typically with a stacking fault plane of (100)TiB. The locations of boron atoms and the lattice mismatch energy between TiB and Ti matrix play key roles in the formation of stacking faults.

Thermal analysis and Raman spectra were carried out in SrBi2Ta2O9 (SBT) nanoparticles to investigate phase transitions. Two anomalies have been observed in temperature dependence of specific heat for SBT nanoparticles. Under the combination with Raman spectra, it indicates that there exists a new ferroelectric intermediate phase in the phase-transition sequence. So we can conclude that the phase-transition sequence in SBT nanoparticles should be ferroelectric-ferroelectric-paraelectric. Moreover, the size effect was discussed in consideration of inner compressive stress in nanoparticles for this special transition behavior. The calculated results show that the SBT nanoparticles keep the ferroelectricity until the particle size is decreased to 4.2 nm.

The in situ synthesized TiB reinforced titanium matrix composites have been prepared by spark plasma sintering at 800–1200 ℃ under 20 MPa for 5 min. The effects of sintering temperature and reinforcement volume fraction on flexural strength, Young’s modulus and fracture toughness of the composites are investigated. The titanium matrix consists of α-Ti and β-Ti phases, and the volume fraction of β-Ti increases with increasing sintering temperatures. The in situ synthesized TiB reinforcements are distributed randomly and uniformly in matrix. The transverse section of TiB has a hexagonal shape aligned along [010] direction, and the crystallographic planes of the TiB needles are always of the type (100); (101) and (101). The 10 vol% TiB reinforced composite sintered at 1000 ℃ exhibits excellent mechanical properties. The flexural strength, Young’s modulus and fracture toughness of this composite are 1560 MPa, 137 GPa and 8.64 MPa·1/2, respectively.