Creep Resistance and Oxidation Behavior of Novel Mo-Si-B-Ti Alloys
Creep Resistance and Oxidation Behavior of Novel Mo-Si-B-Ti Alloys
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DOI：
10.1007/s11837-015-1560-z
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发表时间：
2015-11-01
期刊：
影响因子：
2.6
通讯作者：
Heilmaier, M.
中科院分区：
文献类型：
--
作者：
Azim, M. A.;Schliephake, D.;Heilmaier, M.
Mo-Si-B合金具有熔点高、物相稳定性好、合金化能力大、力学性能和氧化性能合理等优点，是一种很有前途的高温材料。然而，由于在中温和相当高的密度下发生灾难性的氧化，因此需要持续的合金开发。钛的加入稳定了一个新的三元相场，包括Mo5Si3(T1)相而不是Mo3Si(A15)相。由Mo-ss相、T1相和Mo5SiB2(T2)相组成的合金具有很高的蠕变抗力，改善了氧化行为，并显著降低了密度。新的T1相似乎在提高这些新材料的抗氧化性方面起着关键作用，因为这一相在中温和高温下表现出良好的氧化行为。与具有相同组织相排列和尺寸的Mo-Si-B合金或单晶镍基高温合金CMSX-4相比，四元合金具有更好的蠕变性能。主要原因是在加工过程中形成了富钛硅化物析出物。
Mo-Si-B-alloys are promising materials for high-temperature applications because of their high melting point, excellent phase stability, large alloying capabilities, and reasonable mechanical as well as oxidative properties. A continuing alloy development is, however, required because of the catastrophic oxidation taking place at intermediate temperatures and the rather high density. The addition of Ti stabilizes a new ternary phase field including the Mo5Si3 (T1) phase instead of the Mo3Si (A15) phase. Alloys comprising the phases Mo-ss, T1 and Mo5SiB2 (T2) show very high creep resistance, improved oxidation behavior and significantly reduced density. The new T1 phase seems to play a crucial role in the improved oxidation resistance of these new materials, since this phase exhibits excellent oxidation behavior at intermediate and high temperatures. The 4-component alloys possess superior creep behavior compared to Mo-Si-B alloys with the same microstructural phase arrangement and size or to the single crystal Ni-base superalloy CMSX-4. The main reason was found to be the formation of Ti-rich silicide precipitates during processing.