Long-Term Creep Behavior of a CoCrFeNiMn High-Entropy Alloy
- PDF / 9,280,497 Bytes
- 18 Pages / 593.972 x 792 pts Page_size
- 39 Downloads / 247 Views
JMEPEG https://doi.org/10.1007/s11665-020-05103-2
Long-Term Creep Behavior of a CoCrFeNiMn High-Entropy Alloy K.A. Rozman
, M. Detrois, T. Liu, M.C. Gao, P.D. Jablonski, and J.A. Hawk (Submitted August 7, 2020)
The potential of high-entropy alloys (HEAs) to meet or exceed austenitic stainless steel performance with the additional benefit of improved hot corrosion/oxidation resistance makes FCC HEAs attractive for use in energy applications. While shorter-term creep tests have been reported in the literature on HEAs, not all methodologies utilize repeatable techniques. This manuscript reports on over 23,500 accumulated hours of tensile creep testing with adherence to ASTM standards on a melt-solidified ingot of CoCrFeNiMn HEA converted to wrought plate using conventional thermo-mechanical processing techniques. The typical standard creep analyses are reported, i.e., Larson–Miller parameter, Monkman–Grant relationship, activation energy for creep, and creep stress exponents were calculated and compared to previously reported short-term creep tests. Additionally, characteristics of creep fracture and microstructural evolution are reported with cursory dislocation mechanisms investigated. Keywords
creep, creep analysis, high-entropy alloy, SEM, TEM
1. Introduction High-entropy alloys (HEAs), alternatively known as multiprincipal component alloys or composition concentrated solid solution alloys, have been studied intensively because they offer the potential of a good combination of mechanical and physical properties such as tensile strength, toughness, creep, wear and corrosion resistance that make them particularly interesting for use in extreme environments like those in the power generation industry. The National Energy Technology Laboratory (NETL) has a significant research history in HEAs with respect to modeling (Ref 1-11), alloy design (Ref 12-15), large-scale manufacture (Ref 2, 16, 17), mechanical behavior evaluation (Ref 2, 17-21), microstructural characterization (Ref 12, 13, 17, 19, 20, 22-24), and ambient and high-temperature chemical response to environment (Ref 23-26) of HEAs. Specifically, NETL has focused HEA research on the possibilities of using HEAs in the commercial sector, i.e., the energy utilization sector, as structural materials. In that regard, NETLÕs efforts on modeling, while looking at wide ranging topics, still focus on what within these topics can be used at commercial scale, opposed to small < 1 kg melts of high-purity, experimental alloys. The combination of good yield stress and tensile strength with excellent ductility as measured by elongation and reduction in area as a function of temperature (similar to austenitic stainless steel) provided the first indication that these materials might be suitable as structural materials in energy K.A. Rozman, M. Detrois, T. Liu, and M.C. Gao, National Energy Technology Laboratory, 1450 Queen Avenue S.W, Albany, OR 97321; and Leidos Reserach Support Tearm, 1450 Queen Avenue S.W., Albany, OR 97321; and P.D. Jablonski and J.A. Hawk, National Energy
Data Loading...
