1. Introduction 2. The physical metallurgy of nickel and its alloys 3. Single crystal superalloys for blade applications 4. Superalloys for turbine disc applications 5. Environmental degradation: the role of coatings 6. Summary and future trends.

The Superalloys: Fundamentals and Applications

A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

http://science.sciencemag.org/content/sci/early/2017/08/23/science.aan0177.full.pdf

High dislocation density–induced large ductility in deformed and partitioned steels

The design of new low-cost Ti-alloys with high biocompatibility for implant applications, using ubiquitous alloying elements in order to establish the strategic method for suppressing utilization of rare metals, is a challenge To meet the demands of longer human life and implantation in younger patients, the development of novel metallic alloys for biomedical applications is aiming at providing structural materials with excellent chemical, mechanical and biological biocompatibility It is, therefore, likely that the next generation of structural materials for replacing hard human tissue would be of those Ti-alloys that do not contain any of the cytotoxic elements, elements suspected of causing neurological disorders or elements that have allergic effect Among the other mechanical properties, the low Young's modulus alloys have been given a special attention recently, in order to avoid the occurrence of stress shielding after implantation Therefore, many Ti-alloys were developed consisting of biocompatible elements such as Ti, Zr, Nb, Mo, and Ta, and showed excellent mechanical properties including low Young's modulus However, a recent attention was directed towards the development of low cost-alloys that have a minimum amount of the high melting point and high cost rare-earth elements such as Ta, Nb, Mo, and W This comes with substituting these metals with the common low cost, low melting point and biocompatible metals such as Fe, Mn, Sn, and Si, while keeping excellent mechanical properties without deterioration Therefore, the investigation of mechanical and biological biocompatibility of those low-cost Ti-alloys is highly recommended now lead towards commercial alloys with excellent biocompatibility for long-term implantation

Biocompatibility of Ti-alloys for long-term implantation.

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

The corrosion behavior of tubing materials carrying steam at high temperature is of great concern to fossil power plant operators. This is due to the fact that the oxide films formed on the steam side can lead to major failures and consequently to reduced plant availability. The wall loss of the pressure boundary caused by oxidation can increase the hoop stresses and cause premature creep failures; second, the increased insulation of the tubes due to the low thermal conductivity of the oxide film can lead to increased metal temperature, thereby exacerbating the fireside corrosion as well as creep problems. The third concern is that thicker oxides may spall more easily when the plant is cooled down. On restart, the spalled material may lodge somewhere in the system with the potential for causing tube blockages, or it may be swept out with the working fluid and enter the steam turbine causing erosion damage to the turbine nozzles and blades. Failures of tubing and turbine components by these mechanisms have been widely reported in the United States. In view of the importance of the steamside oxidation, a major study of the phenomenon is being carried out as part of a major national program sponsored by the U.S. Department of Energy and the Ohio Coal Development Office. As a prelude to the experimental work, a literature survey was performed to document the state of the art. Results of the review are reported here.

Boiler materials for ultra-supercritical coal power plants - steamside oxidation

Evaluation of the dislocation density and dislocation character in cold rolled Type 304 steel determined by profile analysis of X-ray diffraction

Solid solution softening and hardening in alloyed MoSi2

The system free energy was estimated for the martensite phase of an Fe-Cr-C ternary alloy. The system free energy of the martensite phase is defined as, Gsys=G0+Estr+Esurf, where G0 is the chemical free energy, Esurf is the interfacial energy for the boundaries in the martensite microstructure, and Estr is the elastic strain energy due to the dislocations in the martensite phase. From the experimental results on SEM/EBSD, the interfacial energy was estimated to be 0.05 J/mol for the prior austenite boundary, 0.11 J/mol for the martensite packet boundary and 0.32 J/mol for both the martensite block and the lath boundaries in the asquenched specimen. The total decrement in the interfacial energy accompanying annealing at 873 K for 100 h after quenching was estimated to be about 0.1 J/mol. Also, the elastic strain energy of the asquenched specimen was estimated to be 7.1 J/mol. The total microstructural energy of the martensite phase was about 10 J/mol, which operates as a driving force for the microstructure evolution, e.g., recovery of dislocations and the coarsening of the sub-structures such as martensite-packet, -block and -lath.

Estimation of the System Free Energy of Martensite Phase in an Fe-Cr-C Ternary Alloy

Dislocation densities in 10Cr-5W low-carbon steel that containing carbon content is 0.02C, 0.03C, 0.09C and 0.13C mass% were determinedd from X-ray line analysis based on the modified Williamson-Hall and Warren-Averbach methods. In the as-quenched state the dislocation density in the martensite phase increased with increasing carbon content for these low-carbon steels.

Dislocation Density of Lath Martensite in 10Cr-5W Heat-Resistant Steels

High Zr-containing β-type Ti-based alloys were designed using electronic parameters to investigate experimentally the effect of β-phase stability on their elastic and plastic properties. Texture structures formed by cold rolling or recrystallization were related closely to the β-phase stability and hence affected the mechanical properties. In tensile tests, as the β-phase stability decreased, non-linearity in the elastic zone was enhanced and the work hardening tended to be diminished. Also, it was found that the lower β-phase stability led to the weaker anisotropy of plastic properties, but to the stronger anisotropy of elastic properties.

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Yoshinori Murata

Papers

Evaluation of the dislocation density and dislocation character in cold rolled Type 304 steel determined by profile analysis of X-ray diffraction

Solid solution softening and hardening in alloyed MoSi2

Estimation of the System Free Energy of Martensite Phase in an Fe-Cr-C Ternary Alloy

Dislocation Density of Lath Martensite in 10Cr-5W Heat-Resistant Steels

Change in anisotropy of mechanical properties with β-phase stability in high Zr-containing Ti-based alloys