High-Temperature Creep and Oxidation Behavior of Mo-Si-B Alloys with High Ti Contents
High-Temperature Creep and Oxidation Behavior of Mo-Si-B Alloys with High Ti Contents
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DOI：
10.1007/s11661-013-1944-z
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
D. Schliephake;M. Azim;K. Klinski-Wetzel;B. Gorr;H. Christ;H. Bei;E. George;M. Heilmaier
中科院分区：
文献类型：
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作者：
D. Schliephake;M. Azim;K. Klinski-Wetzel;B. Gorr;H. Christ;H. Bei;E. George;M. Heilmaier
Mo-Si-B系多相合金具有良好的抗氧化性和抗蠕变性，是潜在的高温结构材料。由于它们的密度相对较高，因此当前的研究重点是在 1273 K (1000 °C) 以上温度下添加降低密度的 Ti 对蠕变和氧化行为的影响。通过电弧熔炼合成了两种成分为 Mo-12.5Si-8.5B-27.5Ti 和 Mo-9Si-8B-29Ti（at. pct）的合金，然后通过在 1873 K（1600 °C）下真空退火 150 小时进行均质化。两种合金在 100 至 300 MPa 的应力和 1473 K 和 1573 K（1200 °C 和 1300 °C）的温度下表现出相似的蠕变行为，尽管它们具有不同的金属间化合物体积分数。与最先进的镍基高温合金（单晶 CMSX-4）以及其他 Mo-Si-B 合金相比，它们具有优异的抗蠕变性和更低的密度。维氏硬度测量证实了钛的固溶强化，并且被认为是与不含钛的 Mo-Si-B 合金相比抗蠕变性显着增加的原因，但具有相当的微观结构长度尺度。相对于 Mo-9Si-8B 参考合金，添加 Ti 会降低抗氧化性，因为与二氧化钛基质形成相对多孔的双相层，使氧易于向内扩散。
Multiphase alloys in the Mo-Si-B system are potential high-temperature structural materials due to their good oxidation and creep resistance. Since they suffer from relatively high densities, the current study focuses on the influence of density-reducing Ti additions on creep and oxidation behavior at temperatures above 1273 K (1000 °C). Two alloys with compositions of Mo-12.5Si-8.5B-27.5Ti and Mo-9Si-8B-29Ti (in at. pct) were synthesized by arc melting and then homogenized by annealing in vacuum for 150 hours at 1873 K (1600 °C). Both alloys show similar creep behavior at stresses of 100 to 300 MPa and temperatures of 1473 K and 1573 K (1200 °C and 1300 °C), although they possess different intermetallic volume fractions. They exhibit superior creep resistance and lower density than a state-of-the-art Ni-base superalloy (single-crystalline CMSX-4) as well as other Mo-Si-B alloys. Solid solution strengthening due to Ti was confirmed by Vickers hardness measurements and is believed to be the reason for the significant increase in creep resistance compared to Mo-Si-B alloys without Ti, but with comparable microstructural length scales. The addition of Ti degrades oxidation resistance relative to a Mo-9Si-8B reference alloy due to the formation of a relatively porous duplex layer with titania matrix enabling easy inward diffusion of oxygen.