Effect of alloy composition on microstructure and high temperature properties of Nb–Zr–C ternary alloys

The effect of alloy composition on microstructure and mechanical properties of Nb–Zr–C ternary alloys were investigated. Alloys were prepared arc melting and homogenized. The microstructure of the alloys were characterized by optical microscopy, X-ray diffraction and electron probe microanalysis. Compression tests were conducted from room temperature to 1773 K to determine the stress–strain curves and 0.2% flow stress. Fracture toughness of the alloys was determined using a single-edge-notched specimen under a three-point bending test. The results indicate that the 0.2% flow stress of the Nb–ZrC alloys increases with increasing ZrC content from room to elevated temperature. However, the compressive ductility and fracture toughness decrease with increasing ZrC content. A proper alloy design to obtain balance of high temperature strength and room temperature ductility is also discussed.