We have identified cobalt-base superalloys showing a high-temperature strength greater than those of conventional nickel-base superalloys. The cobalt-base alloys are strengthened by a ternary compound with the L1 2 structure, \({\gamma}^{{^\prime}}\) Co 3 (Al,W), which precipitates in the disordered γ face-centered cubic cobalt matrix with high coherency and with high melting points. We also identified a ternary compound, \({\gamma}^{{^\prime}}\) Ir 3 (Al,W), with the L1 2 structure, which suggests that the Co-Ir-Al-W–base systems with \({\gamma}+{\gamma}^{{^\prime}}\) (Co,Ir) 3 (Al,W) structures offer great promise as candidates for next-generation high-temperature materials.

Cobalt-base high-temperature alloys

Shape memory alloys (SMAs) with high transformation temperatures can enable simplifications and improvements in operating efficiency of many mechanical components designed to operate at tem...

High temperature shape memory alloys

Get the phase diagram information you need at a price you can afford. Key Features: Peer reviewed by the Japanese Committee for Alloy Phase Diagrams. Updated through April 2000. Total number of diagrams = 2,332 (605 are new of greatly revised diagrams; among these 171 are not in Binary Alloy Phase Diagrams, 2nd Edition). Approximately 600 crystal structure tables of systems for which phase diagrams are unknown. You've been asking for a simple book containing just binary phase diagrams and crystal structure data. Desk Handbook: Phase Diagrams for Binary Alloys meets this need, and it presents the most current information. Updates the previous print compilation of binary phase diagrams by 10 years. Presents diagrams in consistent size. Shows the principal axis in atomic per cent, with a secondary axis in weight per cent. Includes an introductory article on phase diagrams and their use. Gives reference to the original literature source. This volume is the latest outgrowth of the phase diagram activity in which ASM International has been involved since 1978.

Desk handbook phase diagrams for binary alloys

Metallic materials are fundamental to advanced aircraft engines. While perceived as mature, emerging computational, experimental and processing innovations are expanding the scope for discovery and implementation of new metallic materials for future generations of advanced propulsion systems.

Alloy design for aircraft engines

A review on fundamental of high entropy alloys with promising high–temperature properties

Phase equilibria between the y and y' phases at 900°C in the Co-(10-70)Ni-Al-W system were determined by electron probe microanalysis (EPMA) and X-ray diffractometry (XRD). It was found that the "/ phase with L1 2 structure continuously exists from the Co side to the Ni side in Co-Ni-Al-W system and that it widens to the low W region with increasing Ni content. The partition of Al into the y' phase increased with Ni content, while the W changed from a y' former to a y former by increase of Ni content. Differential scanning calorimetry (DSC) measurements also revealed that the y' solvus temperature increases with Ni content, while the solidus temperature is hardly affected by such content. The lattice parameter of the y and y' phases and the mismatch decreased with increasing Ni content, which caused the morphologic change of the γ' precipitates from cubes to spheres.

Phase Equilibria and Microstructure on γ' Phase in Co-Ni-Al-W System

Partition behavior of alloying elements and phase transformation temperatures in Co–Al–W-base quaternary systems

A critical evaluation and thermodynamic modeling of the phase diagram and thermodynamic properties have been presented for the Co–Sn system. More attention has been paid to reproduce the thermodynamic properties of the liquid Co–Sn, including the appreciable temperature dependence in the mixing enthalpy and the sign-variable activity with composition observed by experiments. A four-sublattice model has been used to describe the ordering phenomenon between β Co 3 Sn 2 and α Co 3 Sn 2 .

Jun Sato

Papers

Cobalt-base high-temperature alloys

Phase Equilibria and Microstructure on γ' Phase in Co-Ni-Al-W System

Partition behavior of alloying elements and phase transformation temperatures in Co–Al–W-base quaternary systems

A thermodynamic assessment of the Co–Sn system

New ternary compound Co3(Ge, W) with L12 structure