19 What Does the Future Hold? Very few people,if any,probably would have predicted 50 years ago what kind of materials would dominate our technology to- day.Who could foresee the computer revolution and thus the preponderance of silicon in the electronics industry?How many scientists or engineers prognosticated the laser and its impact on communication,data-processing,data storage,and thus on op- tical materials?Was there anybody who foretold,50 years ago, the impact of superalloys,of composites,or of graphite fibers as important materials?Were ceramics not essentially perceived as clay and sand;that is,could anybody anticipate high-tech ce- ramics,including high Te-superconductors,heat-resistant tiles (for space shuttles),silicon carbide engine parts,etc.?And finally, how many people could visualize 50 years ago the impact of plas- tics as one of the prime materials of the present day,or an ac- centuation on recycling and environmental protection? On the other hand,nearly "everybody"predicted only 15 years ago that composites and ceramics for high-temperature engines would be the materials which would enjoy healthy growth rates in the years to come.This,however,has not happened.One of the major funding agencies in the United States (ARPA)has recently stated that the past 20 years have not brought the expected progress in structural ceramics,brittle matrix composites,or intermetallics. It is said that these"exotic"materials may probably never be used in critical parts such as turbine blades because they are too brit- tle,and a balance of properties may probably never be achieved.A 50%cut in support for the ensuing projects has therefore occurred. Instead,a resurgence of substantial interest in metals research may boost,for example,nickel-based superalloys (e.g.,Ni-Al)which are often coated with um-thick heat barriers.These coatings,consist-
19 Very few people, if any, probably would have predicted 50 years ago what kind of materials would dominate our technology today. Who could foresee the computer revolution and thus the preponderance of silicon in the electronics industry? How many scientists or engineers prognosticated the laser and its impact on communication, data-processing, data storage, and thus on optical materials? Was there anybody who foretold, 50 years ago, the impact of superalloys, of composites, or of graphite fibers as important materials? Were ceramics not essentially perceived as clay and sand; that is, could anybody anticipate high-tech ceramics, including high Tc-superconductors, heat-resistant tiles (for space shuttles), silicon carbide engine parts, etc.? And finally, how many people could visualize 50 years ago the impact of plastics as one of the prime materials of the present day, or an accentuation on recycling and environmental protection? On the other hand, nearly “everybody” predicted only 15 years ago that composites and ceramics for high-temperature engines would be the materials which would enjoy healthy growth rates in the years to come. This, however, has not happened. One of the major funding agencies in the United States (ARPA) has recently stated that the past 20 years have not brought the expected progress in structural ceramics, brittle matrix composites, or intermetallics. It is said that these “exotic” materials may probably never be used in critical parts such as turbine blades because they are too brittle, and a balance of properties may probably never be achieved. A 50% cut in support for the ensuing projects has therefore occurred. Instead, a resurgence of substantial interest in metals research may boost, for example, nickel-based superalloys (e.g., Ni–Al) which are often coated with m-thick heat barriers. These coatings, consistWhat Does the Future Hold?
408 19.What Does the Future Hold? ing,for example,of zirconia or Ni-Cr-Al-Y are anticipated to pre- vent the respective alloys in turbine blades from melting or creep- ing.In other words,a change in research support from "exotic' materials to new alloys is presently thought to be more in the na- tional interest.In essence,a shift from structural materials (such as ceramics,composites,etc.)to functional materials (such as smart materials,electromagnetic materials,and optical materials)will probably take place in the next couple of years.Specifically,future funding is anticipated for the development of compact lasers,solid- state lighting through inorganic and organic light-emitting diodes, holographic data storage,thermoelectric materials (used for cool- ing of high Te superconductors,microprocessors,IR detectors,etc.) and for smart materials(which involve a series of sensors that con- trol actuators).Further,a shift from empirical materials selection towards one based on model calculations and on a fundamental understanding of the physics and chemistry of materials science will probably take place.Finally,the exploration of nanostructures and nanotechnology will probably play a major role in future re- search funding. Materials Science has expanded from the traditional metallurgy and ceramics into new areas such as electronic polymers,com- plex fluids,intelligent materials,organic composites,structural composites,biomedical materials (for implants and other medical applications),biomimetics,artificial tissues,biocompatible mate- rials,"auxetic"materials(which grow fatter when stretched),elas- tomers,dielectric ceramics (which yield thinner dielectric layers for more compact electronics),ferroelectric films (for nonvolatile memories),more efficient photovoltaic converters,ceramic su- perconductors,improved battery technologies,self-assembling materials,fuel cell materials,optoelectronics,artificial diamonds, improved sensors (based on metal oxides,or conducting poly- mers),grated light valves,ceramic coatings in air (by plasma de- position),electrostrictive polymers,chemical-mechanical polish- ing,alkali metal thermoelectric converters,luminescent silicon, planar optical displays without phosphors,MEMS,and super- molecular materials.Some materials scientists are interested in green approaches,by entering the field of environmental-biologi- cal science,by developing environmentally friendly processing techniques and by inventing more recyclable materials. Another emerging field is called Nanomaterials by severe plas- tic deformation(SPD)which involves the application of very high strains and flow stresses to work pieces.As the name implies,the re- spective new process yields microstructural features and properties in materials(notably metals and alloys)that differ from those known for conventional cold-worked materials.Specifically,pore-free grain refinements down to nanometer dimensions,and dislocation accu-
ing, for example, of zirconia or Ni–Cr–Al–Y are anticipated to prevent the respective alloys in turbine blades from melting or creeping. In other words, a change in research support from “exotic” materials to new alloys is presently thought to be more in the national interest. In essence, a shift from structural materials (such as ceramics, composites, etc.) to functional materials (such as smart materials, electromagnetic materials, and optical materials) will probably take place in the next couple of years. Specifically, future funding is anticipated for the development of compact lasers, solidstate lighting through inorganic and organic light-emitting diodes, holographic data storage, thermoelectric materials (used for cooling of high Tc superconductors, microprocessors, IR detectors, etc.) and for smart materials (which involve a series of sensors that control actuators). Further, a shift from empirical materials selection towards one based on model calculations and on a fundamental understanding of the physics and chemistry of materials science will probably take place. Finally, the exploration of nanostructures and nanotechnology will probably play a major role in future research funding. Materials Science has expanded from the traditional metallurgy and ceramics into new areas such as electronic polymers, complex fluids, intelligent materials, organic composites, structural composites, biomedical materials (for implants and other medical applications), biomimetics, artificial tissues, biocompatible materials, “auxetic” materials (which grow fatter when stretched), elastomers, dielectric ceramics (which yield thinner dielectric layers for more compact electronics), ferroelectric films (for nonvolatile memories), more efficient photovoltaic converters, ceramic superconductors, improved battery technologies, self-assembling materials, fuel cell materials, optoelectronics, artificial diamonds, improved sensors (based on metal oxides, or conducting polymers), grated light valves, ceramic coatings in air (by plasma deposition), electrostrictive polymers, chemical-mechanical polishing, alkali metal thermoelectric converters, luminescent silicon, planar optical displays without phosphors, MEMS, and supermolecular materials. Some materials scientists are interested in green approaches, by entering the field of environmental-biological science, by developing environmentally friendly processing techniques and by inventing more recyclable materials. Another emerging field is called Nanomaterials by severe plastic deformation (SPD) which involves the application of very high strains and flow stresses to work pieces. As the name implies, the respective new process yields microstructural features and properties in materials (notably metals and alloys) that differ from those known for conventional cold-worked materials. Specifically, pore-free grain refinements down to nanometer dimensions, and dislocation accu- 408 19 • What Does the Future Hold?
19.What Does the Future Hold? 409 mulations up to the limiting density of 1016 m2 are observed.SPD yields an increase in tensile ductility without a substantial loss in strength and fatigue behavior.Furthermore,unusual phase trans- formations leading to highly metastable states have been reported and are associated with a formation of supersaturated solid solu- tions,disordering,amorphization,and a high thermal stability.More- over,superplastic elongations in alloys that are generally not super- plastic can be achieved.This affords a superplastic flow at strain rates significantly faster than in conventional alloys,enabling the rapid fabrication of complex parts.Finally,the magnetic properties of se- verely plastic deformed materials are different from their conven- tional counterparts.In particular,one observes an enhanced rema- nence in hard magnetic materials,a decrease of coercivity,(i.e.energy loss)in soft magnetic materials,and an induced magnetic anisotropy. In short,the field of materials science is extending into new territory and this trend is expected to continue. Still,"Predictions are quite difficult to make,particularly if they pertain to the future."As an example,a U.S.congressman suggested at the end of the 19th century that the patent office should be abolished,"since all major inventions have been made already."Moreover,it has been shown more than once that ex- trapolations of the present knowledge and accomplishments into the years which lay ahead were flatly wrong.Thus,utmost care needs to be exercised when projections are made.To demonstrate this,Figure 19.1 displays the development of essential materials properties during the 20th century. One particular graph that demonstrates essentially correct pre- dictions is worthy of some considerations.Figure 19.1 (d)depicts the number of transistors on a semiconductor chip in yearly inter- vals and reveals that initially the transistor density doubles about every 12 months.This plot,which was empirically deduced from earlier production figures (by an extrapolation of only three earlier data points),was dubbed Moore's law (after Gordon E.Moore at Fairchild Semiconductor)and depicts a log-linear relationship be- tween device complexity and time.This type of prediction into the future is often referred to as a controlling variable,or a self-fulfilling prophecy since each computer chip manufacturer knows what the competitor will present in a given amount of time and acts accord- ingly.In other words,Moore's law involves human ingenuity for progress rather than physics.Higher transistor densities means higher processing speeds,lower power consumption,better relia- bility,and reduced cost.Beginning in the mid-seventies,the slope became less steep but still behaved in a log-linear fashion,and the rate of density doubling slowed down to every 18 months.(At the same time interval the magnetic storage density on hard disk drives doubled every 3 years.)
mulations up to the limiting density of 1016 m-2 are observed. SPD yields an increase in tensile ductility without a substantial loss in strength and fatigue behavior. Furthermore, unusual phase transformations leading to highly metastable states have been reported and are associated with a formation of supersaturated solid solutions, disordering, amorphization, and a high thermal stability. Moreover, superplastic elongations in alloys that are generally not superplastic can be achieved. This affords a superplastic flow at strain rates significantly faster than in conventional alloys, enabling the rapid fabrication of complex parts. Finally, the magnetic properties of severely plastic deformed materials are different from their conventional counterparts. In particular, one observes an enhanced remanence in hard magnetic materials, a decrease of coercivity, (i.e. energy loss) in soft magnetic materials, and an induced magnetic anisotropy. In short, the field of materials science is extending into new territory and this trend is expected to continue. Still, “Predictions are quite difficult to make, particularly if they pertain to the future.” As an example, a U.S. congressman suggested at the end of the 19th century that the patent office should be abolished, “since all major inventions have been made already.” Moreover, it has been shown more than once that extrapolations of the present knowledge and accomplishments into the years which lay ahead were flatly wrong. Thus, utmost care needs to be exercised when projections are made. To demonstrate this, Figure 19.1 displays the development of essential materials properties during the 20th century. One particular graph that demonstrates essentially correct predictions is worthy of some considerations. Figure 19.1 (d) depicts the number of transistors on a semiconductor chip in yearly intervals and reveals that initially the transistor density doubles about every 12 months. This plot, which was empirically deduced from earlier production figures (by an extrapolation of only three earlier data points), was dubbed Moore’s law (after Gordon E. Moore at Fairchild Semiconductor) and depicts a log-linear relationship between device complexity and time. This type of prediction into the future is often referred to as a controlling variable, or a self-fulfilling prophecy since each computer chip manufacturer knows what the competitor will present in a given amount of time and acts accordingly. In other words, Moore’s law involves human ingenuity for progress rather than physics. Higher transistor densities means higher processing speeds, lower power consumption, better reliability, and reduced cost. Beginning in the mid-seventies, the slope became less steep but still behaved in a log-linear fashion, and the rate of density doubling slowed down to every 18 months. (At the same time interval the magnetic storage density on hard disk drives doubled every 3 years.) 19 • What Does the Future Hold? 409
410 19.What Does the Future Hold? Strength of permanent magnets Operating temperatures of engines 40 Nd2FeB 1600 T Sm2(Co,Fe,Cu)7 (C) 30 1200 Turbojet 800 Air-cooled CosSm engine Steam 10 AlNiCo 400 engine Steel 1900 20 40 60 80 1900 20 40 6080 Year Year (a) (b) Critical temperature Components per chip for superconductors T 108 (K) 125 103 Three 10 dimensional 10 10 MOS 39 103 23 17 103 4.2 10 Bipolar ZZ7ZZZ☑ 1 1911 1953 19731988 1960 1970 1980 1990 Year Year (c) (d) FIGURE 19.1.Improve- ments of materials On the other hand,for each doubling of performance,new and properties during the more sophisticated production facilities which may have price tags 20th century. of about twice the previous factory,have to be built.Specifically, it is predicted that by 2005 a single chip fabrication facility will cost 10 billion dollars or 80%of Intel's net worth.Thus,eventually there may be no economic incentive anymore to make transistors smaller unless computer chip companies team together(such as IBM and Toshiba,or Motorola and Siemens)and share a given facility
On the other hand, for each doubling of performance, new and more sophisticated production facilities which may have price tags of about twice the previous factory, have to be built. Specifically, it is predicted that by 2005 a single chip fabrication facility will cost 10 billion dollars or 80 % of Intel’s net worth. Thus, eventually there may be no economic incentive anymore to make transistors smaller unless computer chip companies team together (such as IBM and Toshiba, or Motorola and Siemens) and share a given facility. 410 19 • What Does the Future Hold? FIGURE 19.1. Improvements of materials properties during the 20th century. 10 20 30 40 1900 20 40 60 80 1600 20 40 60 80 400 800 1200 1900 Year (BH)max (MGOe) Steel AlNiCo Co5Sm Sm2(Co, Fe, Cu)17 Nd2Fe14B Strength of permanent magnets Operating temperatures of engines (a) (b) Year T (C) Steam engine Air-cooled engine Turbojet 1960 1970 1980 1990 1 101 102 103 104 105 106 107 108 (d) (c) Year 1911 1953 1988 1973 Year Components per chip Bipolar MOS Three dimensional Components per chip 4.2 17 23 39 125 T (K) Critical temperature for superconductors
19.What Does the Future Hold? 411 While the substantial improvement of physical properties during the past 40 years is certainly impressive,it probably would be wrong to assume that a similar sharp rise would continue in the next decade or two.Indeed,certain limitations exist when,for example,atom- istic dimensions are reached.This may stifle further progress as long as the same conventional methods are applied.In other words,new, innovative concepts are needed instead and probably will be found. One may only speculate what kinds of discoveries might be made by the next generation of scientists and engineers if they would let their imagination roam freely into yet unexplored realms.Among these discoveries may be: A completely different family of materials which are not de- rived from already existing substances but are instead newly created by modifications of genes,that is,by gene technology. These biologically generated materials could possibly be custom-designed with respect to their physical properties,sta- bility,and their recyclability.They may be created from re- newable,inexhaustible resources or by bacteriologic transfor- mations of already existing products. The energy of the future may not be generated by burning wood, coal,or oil,or by involving fissionable or fusionable elements, but by exploiting hitherto unknown"disturbances"that are nei- ther electromagnetic nor of particle nature.This energy source may be tapped,should it exist,and it is hoped that mankind will have developed at that point a high degree of morality so that it may not be misused for destructive purposes. We are presently quite fixated on the concept that matter con- sists exclusively of atoms built from protons,neutrons,electrons, and a handful of other particles.Is it not possible that another type of matter does exist which is built of different particles be- yond our present imagination?Maybe this alternate form of mat- ter will be discovered in the next 50 years,should it exist. The abundance of radioactive waste surely will be a burden to future generations.New techniques may be found which are capable of manipulating the ratio of protons and neutrons in radioactive elements which will transform them into nonradi- ating isotopes. The transition temperature at which superconduction com- mences may again be substantially raised by employing new materials which have a striking similarity to fibers spun by an- imals or which are otherwise created in the body of animals or humans such as in nerve cells. Smart acoustic materials may be discovered which compen- sate incoming sound with a complementary sound,thus elim- inating any noise.In particular,the acoustical properties of
While the substantial improvement of physical properties during the past 40 years is certainly impressive, it probably would be wrong to assume that a similar sharp rise would continue in the next decade or two. Indeed, certain limitations exist when, for example, atomistic dimensions are reached. This may stifle further progress as long as the same conventional methods are applied. In other words, new, innovative concepts are needed instead and probably will be found. One may only speculate what kinds of discoveries might be made by the next generation of scientists and engineers if they would let their imagination roam freely into yet unexplored realms. Among these discoveries may be: • A completely different family of materials which are not derived from already existing substances but are instead newly created by modifications of genes, that is, by gene technology. These biologically generated materials could possibly be custom-designed with respect to their physical properties, stability, and their recyclability. They may be created from renewable, inexhaustible resources or by bacteriologic transformations of already existing products. • The energy of the future may not be generated by burning wood, coal, or oil, or by involving fissionable or fusionable elements, but by exploiting hitherto unknown “disturbances” that are neither electromagnetic nor of particle nature. This energy source may be tapped, should it exist, and it is hoped that mankind will have developed at that point a high degree of morality so that it may not be misused for destructive purposes. • We are presently quite fixated on the concept that matter consists exclusively of atoms built from protons, neutrons, electrons, and a handful of other particles. Is it not possible that another type of matter does exist which is built of different particles beyond our present imagination? Maybe this alternate form of matter will be discovered in the next 50 years, should it exist. • The abundance of radioactive waste surely will be a burden to future generations. New techniques may be found which are capable of manipulating the ratio of protons and neutrons in radioactive elements which will transform them into nonradiating isotopes. • The transition temperature at which superconduction commences may again be substantially raised by employing new materials which have a striking similarity to fibers spun by animals or which are otherwise created in the body of animals or humans such as in nerve cells. • Smart acoustic materials may be discovered which compensate incoming sound with a complementary sound, thus eliminating any noise. In particular, the acoustical properties of 19 • What Does the Future Hold? 411
412 19.What Does the Future Hold? materials will probably be studied more intensely in the future than they have been in the past. The storage of energy in batteries,etc.,is at present most ineffi- cient and requires bulky devices.New techniques will probably be discovered that raise the energy to mass ratio and increase the efficiency by involving a plasma technology,which is harnessed in containers consisting of high-temperature resistant materials. Materials may be found which,when weakened by fatigue or cracking,will activate a self-healing mechanism that returns the material,while in use,to its originally intended properties without external intervention. New types of trees or plant species will be genetically engi- neered which can be harvested in about 7-8 years rather than in the present 30-year time interval. The process of photosynthesis may be copied and used to cre- ate new materials and energy. These few examples may serve as stimuli for future research and thus may lead materials science into new dimensions for the third millennium.It is hoped that future developments will be for the betterment of mankind (and not for its destrucion)since science will be increasingly linked to societal issues. The public seems to be more and more dissatisfied by the fact that the substantial investments which are expended for science and education so far have not solved the problems of society.It almost seems that,with expanding technologies and the consequential rise in the amount of "desirable"consumer goods,the gap between the "haves"and the "have nots"steadily widens.This may be a con- tributing factor to the social unrest and the mindless crimes against property and human lives.Thus,a concerted effort by government, academia,and industry has to be initiated in the near future to find out how educational institutions in general and scholars in partic- ular can contribute to the national welfare.It is imperative that our thinking and our deeds are less governed by money,rules,regula- tions,and mindless laws but instead by our forces of the heart,that is,our caring,compassion,and love for others,including the less fortunate individuals,in other parts of the world.It seems that the problems may be solved only when the next generation is educated in body,mind,and spirit,that is,beyond the factual knowledge of science.Specifically,the rising generation has to be taught to ap- preciate and especially respect the history of mankind,the cultures of other countries,the arts,in their diversity and their important place in life.Moreover,we need to appreciate the beauty but also the vulnerability of Planet Earth,which requires our caring re- sponsibility for life in all its varied forms for generations to come. It is hoped that this book has made a contribution toward this goal
materials will probably be studied more intensely in the future than they have been in the past. • The storage of energy in batteries, etc., is at present most inefficient and requires bulky devices. New techniques will probably be discovered that raise the energy to mass ratio and increase the efficiency by involving a plasma technology, which is harnessed in containers consisting of high-temperature resistant materials. • Materials may be found which, when weakened by fatigue or cracking, will activate a self-healing mechanism that returns the material, while in use, to its originally intended properties without external intervention. • New types of trees or plant species will be genetically engineered which can be harvested in about 7–8 years rather than in the present 30-year time interval. • The process of photosynthesis may be copied and used to create new materials and energy. These few examples may serve as stimuli for future research and thus may lead materials science into new dimensions for the third millennium. It is hoped that future developments will be for the betterment of mankind (and not for its destrucion) since science will be increasingly linked to societal issues. The public seems to be more and more dissatisfied by the fact that the substantial investments which are expended for science and education so far have not solved the problems of society. It almost seems that, with expanding technologies and the consequential rise in the amount of “desirable” consumer goods, the gap between the “haves” and the “have nots” steadily widens. This may be a contributing factor to the social unrest and the mindless crimes against property and human lives. Thus, a concerted effort by government, academia, and industry has to be initiated in the near future to find out how educational institutions in general and scholars in particular can contribute to the national welfare. It is imperative that our thinking and our deeds are less governed by money, rules, regulations, and mindless laws but instead by our forces of the heart, that is, our caring, compassion, and love for others, including the less fortunate individuals, in other parts of the world. It seems that the problems may be solved only when the next generation is educated in body, mind, and spirit, that is, beyond the factual knowledge of science. Specifically, the rising generation has to be taught to appreciate and especially respect the history of mankind, the cultures of other countries, the arts, in their diversity and their important place in life. Moreover, we need to appreciate the beauty but also the vulnerability of Planet Earth, which requires our caring responsibility for life in all its varied forms for generations to come. It is hoped that this book has made a contribution toward this goal. 412 19 • What Does the Future Hold?