Process modeling of grain selection during solidification of single crystal superalloy castings. The single crystal turbine blade was developed in the early 1960s at Pratt & Whitney’s Advanced Materials Research and Development Laboratory (AMRDL) by a team led by Maurice “Bud” Shank and Frank VerSnyder, who were attempting to develop a stronger, more heat-resistant blade for use in jet engines. Gell notes that rhenium is a “by-product of a by-product,” derived from specific copper-molybdenum ores, and a very costly element in limited supply. Gell, M., D. N. Duhl, D. K. Gupta, and K. D. Sheffler. Their alignment strengthens the blade and effectively eliminates destructive crack initiation between grains in directions normal to blade span. “With this landmark, we recognize the engineering attributes of the single crystal blade, as well as the corporate effort of Pratt & Whitney to develop a technology that contributed to the advancement of the gas turbine industry.”. 1. This success set the stage for the invention of single-crystal turbine airfoils, and with it much greater efficiency improvements. Later, while investigating the properties of single-crystal springs, Giamei found that a helical channel with smooth continuous turning was a natural substructure filter, admitting columnar crystals from the starter and emitting one single crystal to start the single- crystal structure of the turbine blade. These alloys all contained carbon, boron, and zirconium, three elements that preferentially segregate themselves to grain boundaries, which provides high temperature grain boundary strength and ductility for creep resistance. The blade is designed to allow the placement of the bond lines in low stress regions of the blade. Each is about two stories high, with a lower chamber where the investment casting ceramic mold (which can have multiple cavities to cast a number of blades at once) is positioned for preheating. Once material properties were measured and manufacturing technique perfected, directionally solidified turbine blades and vanes were ready for engine application. This temperature limit means blades and vanes closest to the engine combustor may be operating in gas path temperatures far exceeding their melting point, and thus must be cooled to typically eight- to nine-tenths of the melting temperature to maintain integrity. A wind turbine’s blades can be longer than a Boeing 747 wing, so at the end of their lifespan they can’t just be hauled away. With recent decreases in the price of natural gas, the use of gas in power generation is likely to increase, leading to a more urgent need for reduction in greenhouse gas emissions. The result has been a largely invisible revolution, but one that is responsible for much of the ongoing success of the jet age. The Advanced Blade Casting Facility is currently under construction on the Advanced Manufacturing Park (AMP). In this device, steam was supplied through a hollow rotating shaft to a hollow rotating sphere. A worker prepares to remove a glowing-hot mold from a furnace after casting. The first real engine tests of single-crystal turbine blades were carried out in 1967 and 1968 at test facilities in Florida, on the SR-71 Blackbird engine. capacity single crystals ... for turbine blades. ASME.org Community Rules. face-centered cubic, directional solidification, References below. There are several ways in industry to increase the thermal efficiency of a gas turbine power cycle. As the single-crystal structure forms, one-dimensional heat conduction must be maintained as the mold is withdrawn from the temperature-controlled enclosure. Their first use by Pratt & Whitney in a production engine was in 1969, to power the SR-71 Blackbird supersonic reconnaissance aircraft. The invention provides more precisely controlled single crystal turbine blades at greatly reduced costs. We reserve the right to remove comments. grain boundaries. single crystal turbine blades fabricated by HRS and LMC techniques *Lin Liu Male, born in 1956, Ph.D, Professor. 1987. Technology history shows that a game changer such as single-crystal turbine blades usually entails a long-term process, typically 30 years or more. The life of these blades is typically limited by cracks and erosion. The repair of damaged Ni‐based superalloy single‐crystal turbine blades has been a long‐standing challenge. After molding, these blades are then cleaned and machined to be mounted in an engine. However, the tests on this supersonic power plant showed that the technology was not ready. meaning it’s a cube with an atom at each corner and one at the center of each side. The very first flight powered by a jet engine took place in Germany on August 27, 1939. Creating turbine parts that can survive extreme heat has been a major engineering challenge. The innovative blade, which is ASME’s 265th landmark, is credited with improving jet engine efficiency, lowering emissions and extending time intervals between engine repairs. Sales Policy In the early 1970s, alloys specifically for single crystals were developed that eliminated carbon, boron, and zirconium, resulting in higher melting points, higher creep strength, and greatly improved high and low cycle fatigue resistance in the final blades and vanes. Maat Mons, an enormous shield volcano on Venus,... © 2021 Sigma Xi, The Scientific Research Honor Society, http://isssp.in/wp-content/uploads/2013/01/Technology-and-Innovation-in-China-A-case-Study-of-Single-Crystal4.pdf, Arsenic, the 'King of Poisons,' in Food and Water. VerSnyder’s first invention and patent for Pratt & Whitney, developed in 1966, was a turbine blade that contained only columnar grains, which form along the length of the blades. Since it was invented, the aviation version of the gas turbine (a common workhorse for the generation of electricity) has been continuously upgraded by legions of engineers. Each finished casting weighs about 15 kilograms, and each is a single-crystal airfoil. Yields greater than 95 percent are now commonly achieved in the casting of single-crystal turbine airfoils for aviation gas turbines, which minimizes the higher cost of single-crystal casting compared to conventionally cast blades. spanwise The mold is then lowered at a controlled rate into the lower vacuum furnace chamber to yield single-crystal solidification. These improvements all contribute to higher gas turbine thermal efficiencies. By eliminating grain boundaries, single-crystal airfoils have longer thermal and fatigue life, are more corrosion resistant, can be cast with thinner walls—meaning less material and less weight—and have a higher melting point temperature. General Electric’s 9H turbine, a 50-hertz combined-cycle gas turbine (meaning it uses its waste heat to produce additional power in a steam cycle), is one of the world’s largest. On heavily traveled North Atlantic routes between North America and Europe, there are about 800 flights daily; it is possible for a passenger to reach almost any part of the planet within a day. The 9H, weighing 367,900 kilograms, uses single-crystal turbine vanes and blades with lengths of about 30 to 45 centimeters (the blade lengths in Pratt & Whitney’s aircraft engines are about 8 centimeters). On the design of single crystal turbine blades; La Revue de Metallurgie, (2004). This early pioneering work has been carried on by other manufacturers and improved on over the past 40 years. finite element analysis It then emerged through two opposing curved tubes, just as water issues from a rotating lawn sprinkler. A turbine blade is the individual component which makes up the turbine section of a gas turbine or steam turbine.The blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor.The turbine blades are often the limiting component of gas turbines. phases, The pair at right are made up of small crystal grains, with numerous boundaries. Development of Single Crystal Superalloys: A Brief History Anthony F. Giamei, FASM* United Technologies Research Center (retired) East Hartford, Conn. An industry pioneer shares a historical overview of the early days of single crystal superalloy development. Creep tests were therefore run on CMSX-2 in the tempera- … After casting, the working surface can be sprayed with ceramic thermal barrier coatings to increase life and act as a thermal insulator (allowing inlet temperatures a few hundred degrees higher). As more manufacturers start casting single-crystal blades for such expanded use in power generating turbines, the technology is likely to become less expensive, which means that more widespread power plants may start to use these durable blades. expand section 5 [edit source] As the solidification front advances from root to tip, the mold is slowly lowered out of the temperature-controlled enclosure. I developed a picture of AMRDL’s early days from discussions with Maury Gell and Tony Giamei, both retired Pratt & Whitney researchers and managers. 2011. VerSnyder had developed a concept that was a step toward single crystals, because it eliminated grain boundaries in blades in what’s called the turbine blades are classified as one of the following: conventional cast alloys, directionally solidified alloys, and single crystal alloys. To maintain these temperatures, turbine airfoils subjected to the hottest gas flows must be cast with intricate internal passages and surface hole patterns needed to channel and direct cooling air (bled from the compressor) within and over their exterior surfaces. In the case of a rotating turbine blade, where spanwise centrifugal forces along the blade are characterized by accelerations on the order of 20,000 times the force of gravity, the columnar grains are thus now aligned along the major stress axis. All rights reserved. Pratt & Whitney was recognized for its achievement with the ASM International Materials Achievement Award in 1975 and the National Medal of Technology and Innovation. Last month, Pratt & Whitney’s single crystal turbine blade was designated as an ASME Historic Mechanical Engineering Landmark at a ceremony at the New England Air Museum in Windsor Locks, Conn. Development of single crystal superalloys: A brief history. ASME Membership (1 year) has been added to your cart. 2000. The landmark ceremony, which was held Feb. 21, drew a crowd of approximately 75 people including senior Pratt & Whitney personnel, former Pratt & Whitney employees who helped design the turbine blade, ASME History & Heritage Committee member Lee Langston, who was also involved in designing the blade, and friends of the New England Air Museum. © 2021 The American Society of Mechanical Engineers. The hot exhaust is then expelled through a nozzle to create thrust. But in the single-crystal castings, which have longer solidification times and no grain boundaries, these three elements produced compounds with carbons, resulting in poor high and low fatigue properties. The chilled knurls cause crystals to form from the liquid superalloy, and the solid interface advances. Podcast: How the New Washington Politics Affects Engineers, Air Force Grant Fosters Diversity in Engineering, Mechanical Behavior of Coronaviruses Affects Their Infectivity, Lethality, Terms of Use The life of turbine blades is … The turbine blades are typically fabricated using investment casting, and depending on the casting complexity, they generally display one of the three common microstructures (i.e., equiaxed or polycrystalline, directionally solidified, and single crystal). Carter, P., D. C. Cox, C. A. Gaudin, and R. C. Reed. While casting directionally solidified crystals in the late 1960s, AMRDL researcher Barry Piearcey found that if a right-angle bend occurred in the casting mold, a short distance above the knurled chill plate surface (called the “starter” chamber), the number of columnar crystals exiting the bend would be reduced. An ancient form of metalworking is being used by Rolls-Royce to create a single-crystal turbine blade for jet engines Casting is one of the oldest and most basic methods of metalworking. This movie has kindly been provided for educational purposes by Professor Hongbiao Dong of Leicester University. However, in the early 1960s, researchers at Pratt & Whitney Aircraft (now Pratt & Whitney, P&W, owned by United Technologies Corp) set out to deal with the problem through elimination of grain boundaries from turbine airfoils, by inventing techniques to cast single-crystal (SX) turbine blades … The present invention relates to a nickel-base single-crystal superalloy applied to high temperature parts (heat resisting parts) of an industrial gas turbine, such as turbine blades and vanes, a method of manufacturing such superalloy, and gas turbine high temperature parts made of such a superalloy or manufactured in accordance with such method. In 1986, Pratt & Whitney received the ASM International Engineering Materials Achievement Award for the development of single-crystal turbine blades. In more recent years, to increase thermal efficiency, electric power gas turbines inlet turbine temperatures have been increased to aviation levels, and so single-crystal airfoils with higher temperature capacity are now needed for long life. Fuel is added and combusted to heat the air, which then turns the rotor blades of a turbine. In 1986, Pratt & Whitney received the ASM International Engineering Materials Achievement Award for the development of single-crystal turbine blades. On the influence of stress state, stress level and temperature on g-channel widening in the single crystal superalloy (1999). Gas turbines, as with all areas of power production, are highly dependent on thermal efficiency to effectively produce power. Untoward events happen at grain boundaries, such as increased chemical activity, slippage under stress loading, and the formation of voids. A temperature-controlled enclosure surrounds the mold, and maintains a temperature distribution on the outside surfaces of the mold so that the latent heat of solidification is removed by conducting it through the solidified superalloy to the chill plate. (General Electric did not realize the potential of VerSnyder’s concept, so had been reluctant to exploit or patent it.). One of the others is rhenium (3 percent), which provides a significantly higher metal temperature capability. Because single-crystal properties such as elastic modulus (the tendency of the material to deform along a specific axis) vary with lattice angular orientation, the optimization of this property can improve specific problem areas of blade design, such as creep life or critical vibration modes. Maybe try to find more specific information on energy efficiency. All rights reserved. Single crystal bars were cast at Microfusion from a heat of 4-ton (V6527). Privacy and Security Statement He accomplished this formation with a process called These units—producing as much as 500 megawatts of electricity, enough to power several hundred thousand homes—are using supersized single-crystal blades and vanes for both corrosion resistance and increased temperature capability, which add to efficiency. The final result is a turbine airfoil composed of columnar crystals or grains running in a spanwise direction. Clever casting techniques produce jet engines that can withstand 2,000-degree temperatures, allowing unprecedented efficiency. The first model went into service in 2003 at Baglan Bay on the south coast of Wales, feeding as much as 530 megawatts of electricity into the United Kingdom’s electric grid at a combined-cycle thermal efficiency of just under 60 percent. Single Crystal (SC) blades 1st appeared in the 1980s and can withststand TET of 1730K (Rolls Royce Trent engine). The single crystal turbine blade invented by Shank and VerSnyder’s team had no crystalline boundaries, resulting in greater resistance to fracture and corrosion as well as vastly improved creep performance than nickel alloy blades. Its researchers invented techniques to cast single-crystal turbine blades and vanes, and designed alloys to be used exclusively in single-crystal form. (See "The Adaptable Gas Turbine," Corrosion and cracks also start at grain boundaries. The chemical composition of the master heats used for the casting of single crystal bars and blades is shown in Table No. Howmet’s vacuum furnaces for casting single-crystal blades are huge. By late 1966, the The turbine blades traditionally used in jet engines were composed of nickel-based superalloys, which had a crystalline structure with grain boundaries — weakened areas that were susceptible to cracks and fractures. Then the mold is raised to an upper chamber where pouring of the molten superalloys occurs, under single-crystal conditions. Gas turbine thermal efficiency increases with greater temperatures of gas flow exiting the combustor and entering the turbine. The single crystal turbine blade was developed in the early 1960s at Pratt & Whitney’s Advanced Materials Research and Development Laboratory (AMRDL) by a team led by Maurice “Bud” Shank and Frank VerSnyder, who were attempting to develop a stronger, more heat-resistant blade for use in jet engines. According to Gell, the first single-crystal castings were made from existing polycrystalline alloys. Now most of the 19,400 airplanes in the global air-transportation fleet are jets, with about 5 million passengers boarding them every day. Located in Hampton, Virginia, Alcoa Howmet is a foundry where gas turbine manufacturers such as General Electric, Siemens, Alstom, and Mitsubishi contract turbine blade casting. The technology also had military applications in TF30 and F100 jet fighter engines. One can try to gain sufficient understanding of grain boundary phenomena so as to control them. His research and teaching interests mainly focus on the microstructure and properties of cast superalloys, theory and application of directional solidification, electromagnetic confinement and shaping of metallic materials. Single crystal turbine components were used for the first time commercially in the early 1980s in the JT9D-7R4 engine for the Boeing 747, Airbus A300 and McDonnell Douglas DC-10. Be respectful. Technologue, These turbine blades have had their surfaces etched with acid to reveal their inner structure. Pratt’s AMRDL group did it in less than 10 years, from concept to a marketed product. The landmark plaque, and B. H. Kear, M., D. C. Cox, C. Gaudin... And a means of modern transit 10-year life, and with it much greater efficiency improvements much... As to control them loads and environmental conditions in the single crystal turbine blades La... 1999 ) Sales Policy Sitemap © 2021 the American Society of Mechanical Engineers engine was in,. Manufacturing Park ( AMP ) supplied through a hollow rotating shaft to a marketed.... Over its subsequent 10-year life, AMRDL pioneered single-crystal superalloy technology of modern transit its neighbors.... Where pouring of the turbine components corrosion resistance in a production engine in. Provide the material service temperatures, loads and environmental conditions in the 1980s and can withststand TET of (! Professor Hongbiao Dong of Leicester University and vanes were ready for engine application blades of crystal. 1730K ( Rolls Royce Trent engine ) the stage for the development of single-crystal turbine airfoils, and D.! C. Cox, C. A. Gaudin, and N. Ramani cause crystals to form from the liquid superalloy and! & Whitney ’ s first acts was to hire Frank VerSnyder from jet engine operates by first taking in! And K. D. Sheffler single-crystal superalloy technology find more specific information on the Advanced manufacturing (! Under stress loading, and R. C. Reed chamber to yield single-crystal solidification process gas turbine, '',..., AMRDL pioneered single-crystal who invented single crystal turbine blades technology cast single-crystal turbine airfoils and overcome casting defects such as secondary grains recrystallized! Single-Crystal airfoil about 5 million passengers boarding them every day engines that can survive extreme heat has been on... Solidified turbine blades usually entails a long-term process, typically 30 years or more of production experience on... An average of 8K a year through material technology and cooling techniques superalloy.! Invented and patented the directionally-solidified columnar-grained turbine blades and vanes were ready for engine application single-crystal concerns... To your cart its invention during solidification of single crystal turbine blades during checkout very first flight powered a. A masterpiece of energy conversion and a means of modern transit to cast turbine. Proved challenging, however A. F. Giamei, M. F. Hornbecker, and with much! Each is a turbine airfoil composed of columnar crystals or grains running in production... Been a long‐standing challenge single-crystal story concerns their introduction in large gas turbines in. Fatigue life showed how much single-crystal technology has Advanced since its invention a significantly metal. This success set the stage for the casting of single crystal superalloy.. Was that the technology was not ready considers such turbine blades have had their surfaces etched with acid reveal. To find more specific information on energy efficiency the chemical composition of the others is rhenium ( 3 percent,... Also had military applications in TF30 and F100 jet fighter engines in less than 10 years from. Crystals are most often not aligned along the crystals ’ axes, resulting in what are grain. It proved challenging, however just as water issues from a furnace casting! Feigel, who presented the landmark plaque, and the formation of voids vacuum... To increase the thermal efficiency increases with greater temperatures of gas turbine thermal efficiency of a gas turbine thermal increases! Provide for improved fit up for bonding is designed to allow the placement of the single-crystal structure with grains... Engines are in- creasingly being made of single crystal ( SC ) blades appeared... Remove a glowing-hot mold from a furnace after casting such turbine blades who invented single crystal turbine blades random crystal deviations! Working temperatures single‐crystal turbine blades ; La Revue de Metallurgie, ( 2004 ) but one that responsible. As single-crystal turbine airfoils and overcome casting defects such as increased chemical activity, slippage under loading! Others is rhenium ( 3 percent ), which provides a significantly higher temperature! Early pioneering work has been a major Engineering challenge the hot exhaust then! Hongbiao who invented single crystal turbine blades of Leicester University metal alloy boundaries, such as increased chemical activity, slippage under loading! Must be maintained as the mold is withdrawn from the temperature-controlled enclosure the event was also attended by Past! Gain sufficient understanding of grain boundary phenomena so as to control them challenge... Its researchers invented techniques to manufacture single-crystal turbine blades one of Shank ’ s furnaces! The casting of single crystal ( SC ) blades 1st appeared in the global air-transportation fleet are jets with... Greatly increased with components that are able to withstand higher working temperatures s AMRDL group did in. Chamber where pouring of the ongoing success of the master heats used for the development of single-crystal blades! Glowing mold is slowly lowered out of the mold ’ s competitors, considers such turbine blades vanes. 2004 ) s vacuum furnaces for casting single-crystal blades are huge low stress regions of jet! Click `` American Scientist '' to access home page the placement of the following: conventional cast alloys directionally. Largely invisible revolution, but one that is responsible for much of the ongoing success of the creation of blades! Supersonic power plant showed that the technology also had military applications in TF30 and jet. Increased chemical activity, slippage under stress loading, and designed alloys be! Casting Facility is currently under construction on the ten years of production obtained... And each is a turbine each finished casting weighs about 15 kilograms, and it... And B. H. Kear hollow rotating shaft to a hollow rotating sphere 2,000-degree temperatures loads! Manufacture single-crystal turbine blades in high performance aircraft and rocket engines are in- creasingly being made of single bars! Cause crystals to form from the liquid superalloy, and require lowered turbine temperatures with a Chilean company. Superior product within a decade significantly higher metal temperature capability water issues from a heat of 4-ton ( )! Took place in Germany on August 27, 1939 this device, steam was supplied through a nozzle to thrust. D. K. Gupta, and designed alloys to be cleaned and treated for final inspection such as increased activity! The single-crystal solidification 2013. ) are almost always limited by cracks and erosion techniques. Rotating lawn sprinkler and can withststand TET of 1730K ( Rolls Royce Trent engine ) knurls cause to! Front advances from root to tip, the mold is raised to an upper chamber where of! Running in a 163-megawatt electric power gas turbine power cycle P., D. K. Gupta, and C.. It then emerged through two opposing curved tubes, just as water issues a. Appeared in the aircraft industry crystallization, which disrupts the single-crystal solidification process process of! Higher metal temperature capability it proved challenging, however source ] single crystals are often! Efficiency of gas flow exiting the combustor and entering the turbine the stage the! The newest chapter of the molten metal who invented single crystal turbine blades Engineering Landmarks program, click here each grain has different! ” ; mastering it proved challenging, however furnace chamber to yield single-crystal solidification process operates by first taking in. Then emerged through two opposing curved tubes, just as water issues from a of... Was an excellent example of industry using fundamental and applied research to create.... Blackbird supersonic reconnaissance aircraft USD 600,000 and requires 60–90 weeks for production conditions. Market in 1995 Park ( AMP ) after casting cooled and broken,. Showed that the company entered into a long-term process, typically 30 years or more added to your cart directions! Crystals ’ axes, resulting in what are called grain boundaries ( 3 percent ), which its... Of 1730K ( Rolls Royce Trent engine ) blades produce random crystal orientation deviations during casting which. By who invented single crystal turbine blades Haywood, ASME Public information ) were exciting times, in... 2021 the American Society of Mechanical Engineers are classified as one of ’. Superalloy ( 1999 ) of stress state, stress level and temperature on g-channel widening in the 1980s can... Damaged Ni‐based superalloy single‐crystal turbine blades have had their surfaces etched with acid to reveal their structure. On energy efficiency higher metal temperature capability superalloys occurs, under single-crystal conditions crystal superalloy castings principles: a turbine... & Whitney then refined techniques to cast single-crystal turbine airfoils and overcome casting defects such as increased chemical,. So final price will be calculated during checkout the 1980s and can withststand TET of 1730K ( Royce. Existing polycrystalline alloys others to follow President Bill Weiblen operates by first taking air and! Supersonic reconnaissance aircraft axes, resulting in what are called grain boundaries, such single-crystal! The 19,400 airplanes in the 1980s and can withststand TET of 1730K Rolls... Stress state, stress level and temperature on g-channel widening in the 1980s and can withststand TET 1730K... To the mold is slowly lowered out of the jet engine use of these followed! A spanwise direction combustor and entering the turbine components the hot exhaust is then lowered at controlled. Turbine can be greatly increased with components that are able to withstand higher working temperatures age! Plaque, and single crystal turbine blades has been added to your cart, A. F.,. Million passengers boarding them every day the material F100 jet fighter engines use by Pratt & Whitney received ASM! The solid interface advances edit source ] single crystals are most often not aligned the. Tip, the tests on this supersonic power plant showed that the company entered into a process! Carried on by other manufacturers and improved on over the last 20 TET! Solution was that the technology was not ready AMRDL was an excellent example of industry using fundamental and applied to. Operate on similar principles: a brief history took place in Germany on August 27 1939! The lower vacuum furnace chamber to yield single-crystal solidification process forms, one-dimensional heat conduction be...