Comparative studies on densification behavior, microstructure, mechanical properties and oxidation resistance of Mo-12Si-10B and Mo3Si-free Mo-26Nb-12Si-10B alloys

摘要

Two bulk Mo-Si-B based alloys (Mo-12Si-10B and Mo-26Nb-12Si-10B (at.%), abbreviated as 0Nb and 26Nb alloy respectively) were fabricated by mechanical alloying and then hot pressing. Comparative studies were carried out on the densification behavior, microstructure, room-temperature fracture toughness, elevated temperature compression and oxidation resistance of these two alloys. The results showed that alloy ONb was composed of (Mo), Mo3Si and Mo5SiB2, while alloy 26Nb was free of Mo3Si and had higher (Mo) content and a little gamma Nb5Si3. Compared to the alloy ONb, alloy 26Nb presented better compactibility, higher room-temperature fracture toughness (8.84 +/- 0.17 vs. 6.77 +/- 0.20 MPa.m(1/2)) and elevated temperature compression strength (851.7 +/- 11.7 vs. 644.2 +/- 10.2 MPa) but worse oxidation resistance.