Preparation of Cf/HfC Composite by Reactive MeltInfiltration Using Hf-Based Alloy

A HfZrSiTa alloy of low melting point was designed by phase diagram calculation and smelted. The Cf/HfC composite was then prepared by reactive melt infiltration at relative low temperature. The open porosity of specimen was 8.45%. By SEM, XRD and EDS, it was found that the melt infiltration microstructure mainly consists of HfC, ZrC, Hf2Si, Zr2Si phases and a small amount of Hf, Zr phases. The as-received Cf/HfC composite, with the flexural strength of 165 MPa, displayed a typical brittle fracture behavior. Ablation properties of the Cf/HfC composite were tested by an oxyacetylene flame. The linear ablation rate was 0.03 mm/s. An oxide barrier layer was formed on the ablation surface and the ablation resistance of the composite has been largely improved.