For the purpose of studying the mechanical property and microstructure of the Hi-Nicalon fiber under aircraft engine simulated environment,Hi-Nicalon fibers were subjected to exposure test at 1 300,1 400,1 500,1 600℃in an gas mixture with an oxygen partial pressure of 8 kPa,argon partial pressure of 78 kPa and H_2O partial pressure of 14 kPa for 1 h,respectively.

The flexural strength of a 3D Hi-Nicalon/SiC composite was tested using the three point bending method at room temperature and the strength distribution was studied based on Weibull distribution.