新型铌合金研究进展

高强铌合金具有比重小、强度高、韧性好、易焊接等优点，是制造高性能航空航天飞行器高温部件的重要材料，研究者通过碳化物强化、高温固溶淬火、大变形挤压、时效和热机械处理等方法研制出系列高强铌合金。航空航天高温结构件减重是研究新型铌合金的一个重要方向，选用密度为6～7．2g／cm^3的系列低密度铌合金，无涂层可在700℃以下工作，加涂层可在1200℃以下工作。铌硅复合材料有望成为在1350℃以上工作的航空发动机叶片材料，研究者通过前期研究筛选出多元Nb-Si-Ti-Al-Cr-X合金作为满足高温应用要求的新型铌合金的研究方向，揭示了铸态显微结构、热处理和热变形（热压、挤压、锻造）条件和机械性能，还研究了Al,Mo，B等合金元素对Nb-Si-Cr系合金抗氧化性能的影响。

Progresses of New Niobium Alloys

High-strength niobium alloys providing low-density, high strength, very good ductility at room temperature, and good weldability, have been used for the high temperature parts of aero space aircraft which have high abilities. In or- der to improve the high-temperature strength and ductility at room temperature, the carbide strengthening, annealing and quenching at high temperature, high reduction of extrusion, aging, thermomechanical treatment have been used. In aero- space applications, weight savings have substantial benefit in system. A class of alloys with densities of 6.2 - 8 g/cm^3 can be used uncoated in air to - 700 ℃ , and have sufficient oxidation resistance at 1 200 ℃ while coating failure is non- catastrophic. Niobium silicide-based in situ composites are hopeful for potential applications in turbine engines with service temperatures up to 1 350 ℃. After a preliminary investigation, the multi-component Nb-Si-Ti-Al-Cr-X system has been se- lected with the aim of developing new alloys that have the potential to meet the required properties for high temperature ap- plications. This paper reviews the microstructures of Nb-Si-Ti-Al-Cr-X alloy under as-cast, heated and hot deformed （ high temperature compression, extrusion, forging） conditions and the mechanical properties. The effect of aluminum, molybde- num, and boron on the oxidation behavior of the Nb-Si-Cr alloy system has also been studied.