Property Responses in Nb-Si-Hf-Ti-Al-W-B-Cr Alloys for High-Temperature Applications
Multi-component Nb-(11,15)Si-5Hf-30Ti-4Al-4W-2B-(8,16)Cr alloys have been proposed, attempting to obtain the Nb-Si based alloys with a comprehensive property. The results show that three phases of NbSS, Nb5Si3 and Laves Cr2Nb exist in the alloys with a Cr content of 16 at%. With increasing Si and Cr contents the fracture toughness KQ decreases, while the oxidation resistance at 1250°C and strength at 1250°C and 1350°C exhibit an increasing tendency. The 15Si-16Cr alloy shows the highest strength and oxidation resistance, and the lowest toughness; they are 385MPa at 1350°C, 215mg/cm2 at 1250°C for 100 h, and 5.45 MPa•m1/2 at room temperature, respectively. The 11Si-8Cr alloy with an NbSS/Nb5Si3 microstructure only has the highest toughness of 11.87 MPa•m1/2, its strength and oxidation resistance are the lowest.
Jian-Feng Nie and Allan Morton
X. X. Yang et al., "Property Responses in Nb-Si-Hf-Ti-Al-W-B-Cr Alloys for High-Temperature Applications", Materials Science Forum, Vols. 654-656, pp. 468-471, 2010