New single crystal superalloys – overview and update

Abstract

Abstract. Single crystal (SX) superalloys have wide application in the high pressure turbine section of aero and industrial gas turbine engines due to the unique combination of properties and performance. Since introduction of single crystal casting technology, SX alloy development has focused on increased temperature capability, and major improvements in alloy performance have been associated with the introduction of new alloying elements, including rhenium (Re) and ruthenium (Ru). 3% Re-containing second generation alloys have seen the greatest market utilization and have become the benchmark alloys for comparing new alloy developments. However, Re and Ru are rare elements with limited production/availability and corresponding high costs. This has resulted in significant escalation of SX alloy costs, resulting in much interest in the development of improved SX superalloys with lower Re or no Re content compared to second generation alloys. Cannon-Muskegon R has developed two new SX superalloys: 1.5% Re CMSX R -8 alloy and CMSX R -7 alloy, which contains no Re, as alternatives to first and second generation alloys for applications which require slightly less ultra high temperature capability compared to current alloys. This paper provides an overview of development and characterization of these SX alloys, including an update on recent results.

Design of Re-free nickel-base single crystal superalloys using modelling and experimental validations

“…Fink et al [6] have proposed 'reduced rhenium' alloys René N500 and René N515 with creep resistance close to René N5 using neural net models, which however rely on proprietary alloy databases. Wahl and Harris [10,11] have disclosed a Re-free alloy CMSX-7 and a low-Re alloy CMSX-8, which bear temperature capabilities close to CMSX-4. Utilizing the CALPHAD method [12][13][14], Reed et al [15,16] have proposed the alloys-by-design methods, which turn out to be successful in designing three new alloys ABD-1/2/3.…”

Variation of Homogenization Pores during Homogenization for Nickel‐Based Single‐Crystal Superalloys

“…Nickle‐based single‐crystal superalloys have excellent high‐temperature mechanical properties, corrosion‐resistance properties, and oxidation‐resistance properties and, thus, are widely used in advanced turbine blades. [ 1–8 ] As a kind of defect, micropore is hard to avoid especially for industrial gas turbine blades with large size and low cooling rate during directional solidification. With micropores, fatigue damage easily occurs under the alternate loading in long‐time service.…”

“…With micropores, fatigue damage easily occurs under the alternate loading in long‐time service. [ 6–10 ] Many investigations have shown that the porosity and the size of micropores are strongly detrimental to the fatigue properties. [ 10–15 ]…”