Development of Exothermically Cast Single-Crystal Mar-M 247 and Derivative Alloys

Abstract

several derivative alloys at 103.5 MPa (15 KSI) and 1093'C (2000'F). Rupture lives of the modified SC alloys were significantly affected by both alloy purity and heat treatment. Critical aspects of vacuum induction refining, exothermic casting technology, alloy development and heat treatment, which contributed to this new class of turbine blades, are reviewed.

Compositional effect on TCP phase formation in Ru-containing Ni-based single crystal superalloys

“…Erickson claimed that lower Co concentrations in a third generation single crystal superalloy CMSX-10 led to the attainment of acceptable alloy stability [14]. However, Co additions were found to prevent the formation of σ phase and µ phase in superalloy MAR-M421 [10] and single crystal superalloy MAR-M247 [11], respectively. Moreover, Walston et al…”

“…However, the mechanism is not quite clear yet, and more Ru additions increase the cost of new generation single crystal superalloys. Furthermore, Co additions were found to prevent the formation of TCP phases in some superalloys [8,[10][11][12], although there has been still controversy associated with the effect of Co additions on microstructural stability [13,14].…”

Influence of Composition on the Microstructure and Mechanical Properties of a Nickel-Base Superalloy Single Crystal

“…It should be noted that Alloy B is also known as NASAIR 100 (2), and that Alloy E is very close to Alloy 3 in (2). A summary of the creep behavior is presented in Figure 6, where the stress dependence of the steady state creep rate is plotted for each Co level.…”

Alloy Design for High Strength Nickel-Base Single Crystal Alloys

“…Representatives of them are ALLOY 454 [4,5], NASAIR 100 [6], CMSX-2 [7,8] maximum(l.32 or 1.37) for alloys to be composed of stable y and y'.…”

“…Fig.3 In Fig. 4, a comparison is made among alloys TMS-1, a representative of designed alloys, and ALLOY 454 [5], NASAIR 100 [6], and Mar-M247(containing C, B, Zr, and Hf) [6], using the specific rupture strength.…”