Residual strains in titanium matrix high-temperature composites

TLDR: In this paper, residual thermal strains and stresses that developed during cooling of a silicon-carbide-fiber-reinforced titanium matrix high-temperature composite were determined by an experimental neutron diffraction technique.

Abstract: Residual thermal strains and stresses that developed during cooling of a silicon-carbide-fiber-reinforced titanium matrix high-temperature composite were determined by an experimental neutron diffraction technique. The results were compared with those obtained by finite element analysis. The study was conducted over the temperature range 20–950 °C. As a result of thermal expansion mismatch, compressive residual strains and stresses were generated in the fibers during cool-down. The axial residual strains and stresses were highly tensile in the matrix, and the matrix underwent plastic deformation. Average transverse residual strains in the matrix were compressive. The measured data compare fairly well with finite element method predictions. The effects of fabrication procedures and thermal processing, such as liquid nitrogen dipping and thermal cycling, on the residual strains were also studied.