The Creep and Oxidation Behaviour of Pesting-Resistant (Mo,Ti)5Si3-Containing Eutectic-Eutectoid Mo-Si-Ti Alloys

In this study we present a series of light-weight (6.24 to 6.42 g/cm(3)), Ti-rich Mo-Si-Ti alloys (>= 40 at.% nominal Ti content) with the hitherto best combination of pesting and creep resistance at 800 and 1200 degrees C, respectively. This has been achieved by fine-scaled eutectic-eutectoid microstructures with substantial fractions of primarily solidified (Mo,Ti)(5)Si-3. (Mo,Ti)(5)Si-3 was found to be oxidation-resistant in these alloys and also beneficial for the creep resistance. The enhanced solidus temperature is of specific relevance with respect to the latter point. The creep resistance is competitive to the non-pesting resistant, but most creep-resistant (among the Mo-Si-Ti alloys) eutectoid alloy Mo-21Si-34Ti developed by Schliephake et al. [Schliephake et al., in Intermetallics 104 (2019) pp. 133-142]. Moreover, it is favourably superior to the commercially applied Ni-based single crystal alloy CMSX-4 for the applied compressive loading conditions under vacuum.

Automated summary

In this study, lightweight Ti-rich Mo-Si-Ti alloys with fine-scaled eutectic-eutectoid microstructures were developed, showing superior oxidation and creep resistance. The presence of (Mo,Ti)5Si-3 in the alloys contributed to their resistance to both oxidation and creep. The creep resistance of these alloys is competitive and surpasses that of other Mo-Si-Ti alloys and the commercially used nickel-based single crystal alloy CMSX-4.