Abstract:To assess the high-temperature creep properties of titanium matrix composites for aircraft skin, the TA15 alloy, TiB/TA15 and TiB/(TA15-Si) composites with network structure were fabricated using low-energy milling and vacuum hot pressing sintering techniques. The results show that introducing TiB and Si can reduce the steady-state creep rate by an order of magnitude at 600 °C compared to the alloy. However, the beneficial effect of Si can be maintained at 700 °C while the positive effect of TiB gradually diminishes due to the pores near TiB and interface debonding. The creep deformation mechanism of the as-sintered TiB/(TA15-Si) composite is primarily governed by dislocation climbing. The high creep resistance at 600 °C can be mainly attributed to the absence of grain boundary α phases, load transfer by TiB whisker, and the hindrance of dislocation movement by silicides. The low steady-state creep rate at 700 °C is mainly resulted from the elimination of grain boundary α phases as well as increased dynamic precipitation of silicides and α₂.

Key words: discontinueously reinforced titanium matrix composite; TiB whisker; network structure; silicides; creep properties