SUPERALLOYS A TECHNICAL GUIDE PDF

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Superalloys: A Technical Guide, 2nd Edition Digital Download (17) It does a good job of achieving its goal as a technical guide to superalloys and is written. Superalloys: a technical guide / M. Donachie, Jr., S. Donachie.—2nd ed This publication is being made available in PDF format as a benefit to members and. Superalloys a Technical Guide - Ebook download as PDF File .pdf), Text File .txt ) or read book online. Superalloys a Technical Guide, ASM superalloy.


Superalloys A Technical Guide Pdf

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Download Citation on ResearchGate | Superalloys: A Technical Guide, 2nd Edition | This book covers virtually all technical aspects related to the selection. Download Citation on ResearchGate | Superalloys: a technical guide | The properties of superalloys and their processing and applications are presented in a. ediclumpoti.ga: Superalloys: A Technical Guide (G) (): Matthew J. Get your site here, or download a FREE site Reading App.

However, resistance to other types of corrosion attack decreased. Superalloys have great oxidation resistance, in many instances, but not enough corrosion resistance. Coating technology is an integral part of superalloy development and application. Lack of a coating means much less ability to use superalloys for extended times at elevated temperatures.

Many alloy elements are added to superalloys in minuscule to major amounts, particularly in the nickel-base alloys. Controlled alloy elements could be as many as 14 or so in some alloys. Nickel and cobalt as well as chromium, tungsten, molybdenum, rhenium, hafnium, and other elements used in superalloys are often expensive and strategic elements that may vary considerably in price and availability over time.

Applications The high-temperature applications of superalloys are extensive, including components for aircraft, chemical plant equipment, and petrochemical equipment. Cooling techniques reduce the actual component metal temperatures to lower levels, and superalloys that can operate at these temperatures are the major components of the hot sections of such engines.

Table 1. It will be noted, however, that not all applications re-. Bolts Blades Stack-gas reheaters Selected automotive components, such as: Turbochargers Exhaust valves Metal processing, such as in: Hot work tools and dies Casting dies Medical components, such as in: Dentistry Prosthetic devices Space vehicle components, such as: Aerodynamically heated skins Rocket-engine parts Heat treating equipment: Trays Fixtures Conveyor belts Nuclear power systems: Control-rod drive mechanisms Valve stems Springs Ducting Chemical and petrochemical industries: A Technical Guide, 1st ed.

Their high strength coupled with corrosion resistance have made certain superalloys standard materials for biomedical devices. What to Look for in This Book The text provides those who desire it a very complete understanding of superalloys.

Donachie, Stephen J. Donachie, p DOI: Selection of Superalloys Overview General Considerations. Selection implies data. Some archival collections of tabulated data on superalloys have been made. Computer-based data collections have been produced.

Unfortunately, there is little likelihood that these collections can serve as much more than a starting point. The subject of design allowables and validated property data is much too large to cover in this book. Tables 2. Except for mill products such as sheet and bar, it is almost never true that the same nominal composition when tested at various laboratories is ever in exactly the same condition. Varying microstructures can mean varying test results. Needless to say, even with identical microstructures, nominal test conditions, and nominal chemistries, there is a random statistical nature to results.

The tracking of data on any one alloy is a laborious task. Consequently, most data compilations consist of an uncritical presentation of data derived from manufacturers and the literature. Caveat emptor! Superalloy Forms. Superalloys are available in cast usually heat treated or otherwise processed or wrought often heat treated or otherwise processed forms.

Cast products may include ingot for subsequent remelting or wrought processing e. Wrought products often are in an intermediate approximation of the shape desired or are mill products, including bar, sheet, wire, plate, and so on. One of the major thrusts of superalloy metallurgy at the end of the 20th century was the production of net shape or near-net shape wrought products. Cast net shapes have been available via investment casting processes for decades. Table 2. Nickel-base 96 continued 91 71 94 81 84 86 98 Nickel-base continued Effect of temperature on h stress-rupture strengths of selected wrought superalloys Rupture strength at: Bar Bar Sheet Cast alloys are found in the hot section areas of gas turbines.

For example. Wrought alloys are more homogenous than cast alloys.

In the intermediate-temperature application areas of gas turbines. Wrought versus Cast Superalloys Wrought Superalloys. Most castings are polycrystalline PC equiaxed. Not all alloy compositions can be made in wrought form.

Wrought alloys generally are considered more ductile than cast alloys. Forgings obviously are also wrought products and take advantage of the superior ductility of wrought material to produce certain larger shapes.

The same composition. The superalloys. Superalloys usually are processed to optimize one property in preference to others.

Cast Superalloys. The PC castings contain many grains that may vary in size from one component to another. Some alloys can only be fabricated and used in cast form. Service Temperatures for Superalloys. The bulk of this text presumes that the application will be at elevated temperature. Even when a superalloy is used in the same product form. By adjustment of processing conditions. Wrought nickel. The majority of superalloys are strengthened by the production of secondary phases precipitates.

Cast alloys are used across the temperature range but particularly at the highest temperatures. Cryogenic applications are covered in Chapter Above that temperature. Costs of actually producing certain net shape wrought products have gone up. Chapter 3 provides detailed information about the metallurgy of all superalloy types. Metals Handbook Effect of temperature on the short-time mechanical properties of selected cast superalloys Ultimate tensile strength at: A Technical Guide Nickel-base Nickel Development Institute The Properties of Superalloys General Comments.

The coarse grain size of PC castings. Strengthening in superalloys is by solid-solution hardening substituted atoms interfere with deformation.. On the other hand For example Castings are intrinsically stronger than forgings at elevated temperature In addition.

A Technical Guide Table Carbide production a favorable distribution of secondary phases interferes with deformation also produces strength. Strength is a relative term. A visual picture also can be obtained for rupture behavior of a few alloys. Because of a melting-point advantage. The deterioration rate of some alloys with time is less than that for other alloys.

Cast cobalt-base alloys. For those interested in property comparisons. This is not an absolute fact. Modern Superalloys. Wrought cobalt-base alloys have found use as combustor parts in gas turbines. Mechanical Properties and the Application of Superalloys. The highest hardener-content nickel-base superalloys became available as cast alloys.

Astroloy no longer dominate the high intermediate-temperature range. Early iron-nickelbase superalloys. Because strength is a function of time. Subsequent iron-nickeland nickel-base superalloys. Hot deformation is the preferred forming pro-. The superalloys are relatively ductile. Figure 2.

For more on the properties of superalloys. Many designs are concerned with the creep behavior of an alloy. Some concern themselves with creep rate. An alloy that may have a longer rupture life and. If alloys are to be used for turbine airfoils.

Cost is a very important factor. As noted in Chapter 1. Selection of alloys is a preliminary step that must be expanded upon to get data and components in a reasonable time frame at acceptable costs. Physical Properties and Density. The essence of superalloy selection for intermediate-temperature applications is that there are standard alloys of capability similar to Waspaloy and down that can be procured and forged by conventional means.

Gas turbine airfoils experience temperatures in this range.

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High-Temperature Applications—Cast Alloys. Powder metallurgy processing enables production of forged components not otherwise processable. A Technical Guide cess. In addition to maximizing creep-rupture strength. If an alloy is to be used as sheet. Good tensile ductility is important. The physical properties. To maximize strength.

An alloy for the most stringent turbine airfoil applications will have a high melting point. For the higherstrength applications. Increases achieved in alloy capability can be negated if a large density increase results as well. Modern cast nickel-base superalloys tend to have densities in the high end of the density range. Density can be important in aircraft gas turbines where increased density can result in increased stress on mating components.

If alloys to be used are intended for massive applications. The lower moduli result from DS processes. Massive parts.

A special type of superalloy. As section thickness is reduced. MA is another such alloy that may have enough strength for a high-pressure turbine blade in aircraft gas turbines. An HPT disk has blades attached. For low-pressure turbine LPT airfoils. A power train in which there are: A disk is a component attached to a shaft and that turns the shaft or is turned by it.

Note that the hot sections occur near the rear of the engine. TMF problems must be minimized by using DS-produced oriented grain or crystal structures to reduce stresses. In the most demanding conditions. For turbine vanes where no centrifugal load exists. A schematic of a typical gas turbine is shown in Fig. Oxide-dispersion-strengthened alloys are not common. MA relies on yttria dispersed in a corrosion-resistant nickel-chromium matrix to provide adequate creep-rupture capability. Typical gas turbine parts made from superalloys consist of the following components.

The disks being considered here would turn the shafts. An Example of Gas Turbine Disks. The various requirements that might have to be met in the choice of material for an HPT disk for a gas turbine engine. At the same time. IN is the alloy of choice for a majority of gas turbine disks. Steels are out of the question. On the other hand. Wrought alloys have better ductility and higher tensile properties than cast alloys.

By checking the available yield and ultimate strengths. An example is the prevalence of IN as the standard low intermediate-temperature turbine disk in aircraft gas turbine engines.

When a cobalt shortage and attendant high alloy prices occurred in the latter part of the s. An additional factor in the selection of an alloy for this disk application becomes the cost and availability of material. Cost and availability. IN had wide acceptance but not necessarily better properties overall than some competitive materials.

Cast alloys are not a satisfactory choice. A disk fracture is a major event. A Technical Guide An alloy with the best ductility and uniformity of properties is indicated for the disk because of the criticality of the application. Yield and ultimate strengths plus LCF resistance were quite satisfactory.

The alloy was available. Wrought iron-nickel-base alloys are a possibility. To summarize the selection process. Up until about This fatigue is LCF and is found at the high-stress. Cobalt-base super- alloys are not in contention here. High yield and ultimate strengths are required to resist the high centrifugal forces caused by rapid rotation and the mass of the disk and its attached blades. Carbides may provide limited strengthening directly e. If body-centered tetragonal bct is added to the list.

Crystal Structures. Secondary phases of value in controlling properties are the fcc carbides MC. The superalloys derive their strength mostly from solid-solution hardeners and precipitated phases. As noted earlier. In addition to macrostructure. That is. In addition to grain size and morphology. Phases in Superalloys. The extent to which they contribute directly to strengthening de-.

Figure 3. When hard sphere models representing the crystal structures of most metals are constructed.

Carbides are found in all three superalloy groups. Ordering is very important in the strengthening of superalloys.

Metals tend to have relatively simple crystal structures. There is no special need to describe the crystal structure of all phases.

Face-centered cubic fcc. Some alloys. Alloys in this last category vary from DL stainless with slight chromium and nickel adjustments. Some carbide. Nickel atoms are always on faces. At the current time ironnickel-base superalloys invariably are used in the wrought condition. The most important class of iron-nickel-base superalloys includes those alloys that are strengthened by intermetallic compound precipitation in an fcc matrix.

Table 3. Introduction to the Alloy Groups Fig. Nickel-Base Superalloys. These minor elements are not customarily found in most cobalt-base alloys. Additional tabular information on phases is provided in Tables 3. Detrimental phases also form in the superalloys. Although there are solid-solution-hardened nickel-base su- pends on the alloy and its processing. These phases are so-called topologically close-packed tcp phases and may not be of concern in trace amounts.

A Technical Guide Fig. Borides may form in the iron-nickeland nickel-base superalloys.. Gamma prime is spherical in ironnickel-base and in some of the older nickel-base alloys. Ti Principal strengthening phase in many nickel. Form of precipitation is important. In the more recently developed nickel-base alloys. Observed in overaged Inconel Randomly distributed carbide. Found in iron-nickel-. Generally observed as a blocky intergranular shape.

Nitrides are observed in alloys containing titanium. For niobium-strengthened nickel-base superalloys. A Technical Guide Table 3. Co 7 Mo. W 6 Observed in iron-nickel. For alloys with titanium and aluminum. Zr N Ti. These three alloys IN An additional dimension of nickel-base superalloys has been the introduction of morphological grain-aspect ratio and orientation control as a means of improving properties.

Nickel-base superalloys are used in both cast and wrought forms. Alloys of this type are IN and IN In fact. Wrought alloy grain sizes tend to be smaller than grain sizes in cast alloys Nb Cr La. Properties in superalloys usually are developed for a given composiTable 3. Nb Al. Cr La. Cr Mo C. Ti Al. Major Elements in Superalloys Re a Not all these effects necessarily occur in a given alloy. Grain size in castings is a direct function of the casting process and.

Grain structure is developed by processing. Chemistry is very important in providing for the level of strength and corrosion properties that may be achieved. Ta Al. Microstructural changes are invariably produced by dissolving all or most of the carbides and other intermetallic precipitate phases e.

Microstructure includes not only grain size and morphology but also the type and distribution of secondary phases in the superalloy austenitic matrix. Ce La. The essential distinction in these alloys is between cast and wrought structures.. Co Al. The cobalt-base superalloys are invariably strengthened by a combination of carbides and solid-solution hardeners.

Hf Cr Cr.. Wrought alloy grain sizes can be varied over a wider range.. Th Cr. Superalloys contain a variety of elements in a large number of combinations to produce desired effects..

Ni Ti Alloying Element Summary. Some elements go into solid solution to provide one or more of the following: Lanthanum has been added to some alloys to promote oxidation resistance.

Chromium is the principal element needed for hot corrosion resistance. Detrimental Tramp Elements in Superalloys. The height of the element blocks indicates the amounts that may be present. The evolution of microstructure has been much more pronounced in the iron-nickel-base and nickel-base superalloys than in cobalt-base alloys. The major alloying elements that may be present in nickel-base superalloys are illustrated in Fig.

A Technical Guide peralloys. Many elements cobalt. Some elements boron. Minor elements carbon and boron are added to form carbides and borides. Elements Causing Brittle Phase Formation. The tcp phases usually have low ductility are brittle and cause loss of mechanical and sometimes corrosion properties when present in anything more than trace amounts. In such cases. All true superalloys contain some chromium plus other elements to promote resistance to environmental degradation. The role of chromium is to promote Cr2O3 formation on the external surface of an alloy.

The most obvious microstruc-. Elements such as silicon. Elements such as magnesium tend to tie up and remove some detrimental elements such as sulfur in the form of a compound.

Microstructure Introduction. Some of the elements mentioned previously produce readily discernible changes in microstructure.

Microprobe and Auger spectroscopic analyses have determined that grain boundaries can be decorated with tramp elements at high local concentrations. A major addition to nickel-base superalloy chemistry in recent years has been the element rhenium. The precise microstructural effects produced are functions of processing and heat treatment. MC carbides tend to decompose and generate other carbides.

Summary of Phases in Iron Nickel. The major phases and form of occurrence in iron-nickel. During heat treatment and service. Other elements. These rafts may be useful for increasing creep-rupture properties.

Carbides in nominal solid-solution alloys may form after extended service exposures. All nickel-base alloys contain this phase as the matrix.

This phase provides very high strength at low-to-intermediate temperatures. This is the principal high-temperature strengthening phase. There are several carbide phases. It appears as spheres or cuboids when properly formed. This precipitate is found in only a few nickel nickel-iron- base alloys. They are mentioned again in Chapter Typical operating microstructures of representative superalloys are shown in Fig. When cast nickel-base superalloys became available in the mids and became necessary for design applications after It is possible to pack more precipitate in the matrix gamma phase this way.

Some principal hardening precipitate characteristics that act to obstruct deformation are: Initial microstructures of all superalloys contained some amount of carbide.

As alloy development proceeded. The ordered precipitates possess an energy antiphase domain boundary or APB rep-. The product in early alloys was. The introduction of preferred positions ordering for individual atoms increases the amount of energy required to pass deformation elements dislocations through a precipitate.

The likelihood of their presence increases as the solute segregation of the ingot increases. Microstructural phase morphology can vary widely. A Technical Guide ron segregates to grain boundaries. How Microstructures Evolved. In the iron-nickel-base and nickel-base precipitation-hardened superalloys which appeared after the development of solutionhardened superalloys. Precipitates strengthen an alloy by impeding the deformation process that takes place under load.

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Typical Microstructures. Some additional microstructures are shown in Appendix B. These phases can cause lowered rupture strength and ductility. Superalloy Strengthening Precipitates and Strength. The optimal situation is for matrix and precipitate to have the same crystal structure and almost the same size of crystal lattice. There are several boride phases. Macrostructures are shown for a polycrystalline PC cast cobalt and a PC cast nickel superalloy and indicate the carbide phases that are usually seen.

Note script carbides in a and b as well as eutectic carbide-cobalt grain-boundary structures in a. IN right. The change in morphology is related to a matrix-precipitate mismatch. Optimal size is a function of the property being measured. It is stable over a relatively narrow range of compositions but possesses remarkable properties that enable it to provide high-temperature strength to ironnickel.

Gamma double prime is a coherent precipitate of composi-. Gamma Prime. It precipitated as spheroidal particles in early nickelbase alloys. Gamma prime is an intermetallic compound of nominal composition Ni3Al with titanium and other elements dissolved in it.

Gamma Double Prime. For wrought superalloys. In creep rupture. Higher APB energies require correspondingly more force for deformation to occur. When size is too large. When the size is too low. Other types of intermetallic phases. In cast alloys. The carbides are particularly essential in the grain boundaries of PC cast alloys for production of desired strength and ductility characteristics.

MC carbides form from the melt and are created either by that reaction or the precipitation from supersaturated solid solutions at high temperatures. Carbide levels in wrought alloys always have been below those in cast alloys.

As noted previously. MC is a high-temperature carbide. M6C carbides gen- Fig. This book covers virtually all technical aspects related to the selection, processing, use, and analysis of superalloys.

The text of the second edition has been completely revised and expanded with many new figures and tables added. In developing this new edition, the focus has been on providing comprehensive and practical coverage of superalloys technology.

Some highlights include the most complete and up-to-date presentation available on alloy melting. Coverage of alloy selection provides many tips and guidelines that the reader can use in identifying an appropriate alloy for a specific application. The relation of properties and microstructure is covered in more detail than in previous books.

ISBN 13: 9780871707499

Convert currency. Add to Basket. Compare all 5 new copies. More information about this seller Contact this seller. Never used!. Seller Inventory P With increasing The derived temperatures are listed in Table 4.

The solidus temperatures determined the microstructural evolution of these alloys. The results are by Thermo-Calc from the thermodynamic database for each listed in Table 5. Co1 microstructures after heat treatment at different temperatures BSE images.

The same general trend was observed in the microstructures. These differences cannot always be explained by the experimental uncertainty of surface-fraction measure. Firstly it can be 5. Discussion: comparison between experimental and thought that they may be due to the fact that the alloys did calculated results not reach full equilibrium experimentally annealing for 5 h at high temperature could have been too short.

The fact that experimental surface ment and calculation in terms of the phase types, except fractions are larger than the calculated ones is likely due for Co1 and Co2. The MC eutectic carbides were always to other factors than non-equilibrium. Indeed, it is probably detected in the microstructure, whereas the chromium car- unsuitable to directly compare surface fractions and volume bides were only observed when their volume fraction was fractions, because of the complex shape of these eutectic sufficient.

It should be a 1. For example, the microstructure of alloy 0. However, the other alloys showed —60 good agreement between the results from thermal analysis 0. Conclusion 0 0. However, 0 b Onset point : 1 The temperatures corresponding to the beginning of melting Fig. DSC curves of Co3 a , magnification of the heating curve b. The attempt was made to derive a proportional relation between the two sets of values. Table 8 shows the [1] E. When [2] C. Sims, W.

The ratio is generally close to 1. Frisk, A. Fernandez Guillermet, J. Alloys Compounds alloys that were analyzed. The values of the remaining alloys — For the M7 C3 carbides, the [6] Z. Liu, Y. Ansara, M. The experimental melting temperatures and the calcu- [8] N. Dupin, I.Order Processing Orders that are placed before p.

All rights reserved. Vacuum levels vary from producer to producer but are in the range of 0. Classified as: Samples of each alloy were treated as follows.

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After that portion of the charge that is feasible is added to the furnace. Special processing—for example. The effects of processing are discussed in more detail in the appropriate chapters. Kotval, J.

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