Mg–Zn/graphite thermal protection materials: study of mechanical properties at high temperature

As the initiative thermal protection materials applied in the field of aerospace industry, the high temperature performance evolution of the dissipation thermal protection materials is essential for keeping the carrying capacity of structure and the integrity of aerodynamic configuration in the aerodynamic environment. In this paper, flexural properties and compression properties of Mg-Zn/Graphite dissipation thermal protection materials are studied by three point bending tests and compression tests from room temperature to 1000 degrees C, and fracture morphologies are observed and analysed by scanning electron microscope. The results showed that the flexural strength and compressive strength of composites were higher than that of matrix by 115 and 84% at the room temperature. With the increasing temperature, the strength of composite showed a downward trend. The fracture scanning showed that the internal defects of composite increased owing to oxidation of metal during the heating process. However, the temperature increased to 1000 degrees C the plush-like oxides covered on fracture surface uniformly and densely, which made the crack propagation energy of the interface between matrix and metal phase increase and it was beneficial to the improvement of strength.