NASA has "Bombed" the Moon today and we have to revisit list of our Lithium end users. We have wrote extensively on Lithium Demand picture and that full electric vehicles mass market - Green Mobility Revolution, will bring necessary increase to the demand side to move lithium prices substantially. According to TRU, Lithium Alloys is the second sector of growth for lithium demand by applications. Recent news on Dubai air traffic increasing even in recession times justifies another look on aerospace development. Another part of the world - emerging markets are just getting started to use commercial airlines and our own bleak picture in air travel maybe not the case for extrapolation. We would prefer to see announcement similar to the plan rolled out by France with billions of investments in electric cars' infrastructure, including compulsory charging points for residential and commercial building, but something must be behind that "Moon Bombed by USA" anyway. We hope that Canada and Argentina will not have to be "liberated" from their Lithium and REE resources one day.
But back to the Moon, NASA and "bombing" as CNBC has put it. We have read recently a very disturbing book "The Next 100 years" and you would think that author was smoking something really strong apart from that it happen to be George Friedman - the founder and CEO of STRATFOR, the world's leading global intelligence and forecasting company.
You have to read it to understand our hesitation, but today's hit on the Moon is a reminder to everybody that Empire could strike back and next wars will be fought from space with bases on the Moon, Battle Stars and Supersonic Missiles. Mr Friedman is a military man, so he writes about war as part of the world order and we hope that the world will be able to do better then that scenario. But the main conclusions on future technological developments can be hardly argued in general and are putting Lithium, other Rare metals and Rare Earth Elements on the map as strategic commodities to be in demand in the nearest future:
1. Electricity as the major power source for end users including military applications.
2. Battery storage systems widely used in all mobility applications.
3. Supersonic missiles and drones are controlling sky and high precision operations are used for ground operations.
4. Satellite systems are moving control of World Trade from the sea level to the space.
We are not in agreement with China potential and USA cynical warfare technological leadership as per book, but we have to agree that once the US Dollar "managed crash" in slow motion" will take its cause, what can move the spirits up with the dollar better, than old and proven currency management tool - war? We can only hope:
"...Universe will give us all a chance and Masters will not chose to spin us into the first option because of.....(you can add any positive thoughts here). In this case we need to plan how to live during Kondratieff Winter until all loss from derivatives will be absorbed by the system. Here is our Gold and Silver ideas will shine, when government will debase FIAT currencies to inflate out debts and Social Security payments unsustainable with real purchasing power of currencies at the same level. Gold and Silver act like a Real Store of Value. Next thing is to find a Big Idea around which you can consolidate the nation and its economy. It can not be Wall Street and Prosperity of Goldman Sachs, idea to sell houses to everybody, who can never afford it, will be felt by everybody for decades to come. We need something which will affect positively everybody very fast, will be big enough to bring structural change to the whole economy, will use at least something competitive left in US Corp., will unleash positive energy of creation and sustainable living in peace with Nature. From economic point of view it must bring back wealth creation based on spending of what is earned, saving and investing in production goods and services with high added value.Such a thing is in existence already and we call it Next Big Thing - Green Mobility revolution based on Electric Cars with new oil - Lithium and REE to drive our Green Bull.We will start our reasoning from the End - it is already happen and US Corp. has to catch up. China is making a leapfrog into electric car next industrial revolution and increasing dramatically its competitive and strategic Power: they are allocating resources where it is matters: high end research applications for everyday life. It is a matter of security - they do not have Oil, they need to keep population happy and bring mobility without destroying what is left out of environment there. Electric cars means New Energy sources, new infrastructure build and new internal consumer demand created. "
"Published: 09 Oct 2009 01:17:40 PST
Aluminum-lithium alloys have been developed primarily to reduce the weight of aircraft and aerospace structures. More recently, they have been investigated for use in cryogenic applications.The major development work began in the 1970-1980, when aluminum producers accelerated the development of aluminum-lithium alloys as replacements for conventional airframe alloys. The lower-density aluminum-lithium alloys were expected to reduce the weight and improve the performance of aircraft.
Commercial aluminum-lithium alloys are targeted as advanced materials for aerospace technology primarily because of their low density, high specific modulus, and excellent fatigue and cryogenic toughness properties. The superior fatigue crack propagation resistance of aluminum-lithium alloys, in comparison with that of traditional 2xxx and 7xxx alloys, is primarily due to high levels of crack tip shielding, meandering crack paths, and the resultant roughness-induced crack closure. However, the fact that these alloys derive their superior properties from the above mechanisms has certain implications with respect to small crack and variable-amplitude behavior.
The principal disadvantages of peak-strength aluminum-lithium alloys are reduced ductility and fracture toughness in the short transverse direction, anisotropy of in-plane properties, the need for cold work to attain peak properties, and accelerated fatigue crack extension rates when cracks are micro structurally small. Commercial Aluminum-Lithium AlloysDevelopment of commercially available aluminum-lithium-base alloys was started by adding lithium to aluminum-copper, aluminum-magnesium, and aluminum-copper-magnesium alloys. These alloys were chosen to superimpose the precipitation-hardening characteristics of aluminum-copper-, aluminum-copper-magnesium-, and aluminum-magnesium-base precipitates to the hardening of lithium-containing precipitates. Proceeding in this manner, alloys 2020 (Al-Cu-Li-Cd), 01429 (Al-Mg-Li), 2090 (Al-Cu-Li), and 2091 and 8090 (Al-Cu-Mg-Li) evolved. Besides these registered alloys, other commercial aluminum-lithium alloys include Weldalite 049 and CP276.
Weldalite 049Chemical composition: Cu - 5.4, Li - 1.3, Ag - 0.4, Mg - 0.4, Zr - 0.14.Weldalite 049 shows high strength in variety of products and tempers. Its natural aging response is extremely strong with cold work (temper T3), and even stronger without cold work (T4); in fact, it has a stronger natural aging response than that of any other known aluminum alloy. Weldalite 049 undergoes reversion during the early stages of artificial aging and its ductility increases significantly up to 24%. Tensile strengths of 700 MPa have been attained in both T6 and 18 tempers produced in the laboratory.
Weldalite 049 has very good weldability. For example, it displays no discernable hot cracking in highly restrained weldment made by gas tungsten arc, gas metal arc and variable polarity plasma arc (VPPA) welding. Extremely high weldment strengths have been reported using conventional 2319 filler, and even higher weldment strengths have been obtained with the use of proprietary Weldalite filler.
Alloy 2090Chemical composition: Cu - 2.7, Li - 2.2, Ag - 0.4, Zr - 0.12.
Alloy 2090 was developed to be a high-strength alloy with 8% lower density and 10% higher elastic modulus than 7075-T6, a major high-strength alloy used in current aircraft structures. Alloy 2090 was registered with the Aluminum Association in 1984. A variety of tempers are being developed to offer useful combinations of strength, toughness, corrosion resistance, damage tolerance, and fabricability.
Because alloy 2090 and its tempers are relatively new and in different phases of registration and characterization, data concerning strength and toughness may be incomplete for some forms.
In general, the engineering characteristics of aluminum-lithium alloys are similar to those of the current 2xxx and 7xxx high-strength alloys used by the aerospace industry. However, some material features of the 2090 products vary somewhat from those of the conventional aluminum alloys and should be considered during the design and material design phase.
These distinct characteristics of 2090 include:
An in-plane anisotropy of tensile properties that is higher than in conventional alloys.
An elevated temperature exposure for the peak-aged tempers (T86, T81 and T83) that shows good stability within 10% of original properties.
Excellent fatigue crack growth behavior.
The need for cold work to achieve optimum properties. In this characteristic, 2090 is similar to 2219 and 2024.
Shape-dependent behavior for extrusions with very high strengths.
Alloy 2090 sheet and plate, and 2090-T86 extrusions have demonstrated excellent resistance to exfoliation corrosion in extensive seacoast exposure tests. The resistance of these alloys and tempers is superior to that of 7075-T6, which, in some product forms, can suffer very severe exfoliation during a two-year seacoast exposure.
The stress-corrosion cracking (SCC) resistance of 2090 is strongly influenced by artificial aging. Tempers that are under-aged, such as T84, may be more susceptible to SCC than the near-peak-aged T83, T81, and T86 tempers.
Alloy 2091Chemical composition: Cu - 2.1, Li - 2.0, Zr - 0.10.
Alloy 2091 was developed to be a damage-tolerant alloy with 8% lower density and 1% higher modulus than 2024-T3, a major high-toughness damage-tolerant alloy currently used for most aircraft structures. Alloy 2091 is also suitable for use in secondary structures where high strength is not critical.
Alloy 2091 has been registered with the Aluminum Association. A variety of tempers are being developed to offer useful combinations of strength, corrosion resistance, damage tolerance, and fabricability. The microstructure of 2091 varies according to product thickness and producer; in general, gages above 3.5 mm have an unrecrystallized microstructure, and lighter gages feature an elongated recrystallized grain structure.
In general, the behavior of 2091 is similar to that of other 2xxx and 7xxx alloys. Material characteristics that have been cause for concern in other aluminum-lithium alloys are of less concern in 2091. Alloy 2091 depends less on cold work to attain its properties than does 2024. The properties of 2091 after elevated-temperature (up to 125℃) exposure are relatively stable in that changes in properties during the lifetime of a component are acceptable for most commercial applications.
The exfoliation resistance of 2091-T84, like that of 2024, varies depending on the microstructure of the product and its quench rate. The more unrecrystallized the structure, the more even the exfoliation attack. However, the exfoliation resistance of 2091 is generally comparable to that of similar gages of 2024-T3.
The microstructural relationship for stress-corrosion cracking in sheet products is the converse of that for exfoliation. As the microstructure becomes more fibrous, the SCC threshold increases. For thicker unrecrystallized structures and thinner elongated recrystallized structures, it is possible to attain an SCC threshold of 240 MPa, which is quite good compared to that of 2024-T3. For thinner products, the threshold varies by gage and producer; it may be as low as 50 to 60% of the yield strength or as high as 75% of the yield strength.
Although fatigue testing on 2091 has been done by a number of labs, producers, and users, the results have been difficult to interpret. The results for 2091 have been superior to those for 2024, roughly equivalent to those for 2024, or inferior to those for 2024. In general, the consensus is that under controlled and similar circumstances, the fatigue properties of 2091-T84 are sufficient to allow it to be used as a substitute for 2024.
Alloy 8090Chemical composition: Li - 2.45, Zr - 0.12, Cu - 1.3, Mg - 0.95.
Alloy 8090 was developed to be a damage-tolerant medium-strength alloy with about 10% lower density and 11% higher modulus than 2024 and 2014, two commonly used aluminum alloys. Its use is aimed at applications where damage tolerance and the lowest possible density are critical. The alloy is available as sheet, plate, extrusions, and forgings and it can also be used for welded applications.
The chemical composition of 8090 has been registered with the Aluminum Association. A variety of tempers have been developed that offer useful combinations of strength, corrosion resistance, damage tolerance, and fabricability.
Because alloy 8090 and its tempers and product forms are relatively new and unregistered, property data are incomplete. The medium-strength products of alloy 8090 are aged to near-peak strength and show small changes in properties after elevated-temperature exposure. The very underaged (damage-tolerant) products will undergo additional aging upon exposure to elevated temperatures.
Changes in strength and toughness at cryogenic temperatures are more pronounced in 8090 than in conventional aluminum alloys: 8090 has a substantially higher strength and toughness at cryogenic temperatures.
The improving quality of commercially available aluminum-lithium alloys such as 8090 has resulted in significant improvements in short-transverse ductility and, consequently, short-transverse tensile strength. Research on the short-transverse fracture toughness of 8090 has shown that the property reaches a minimum plateau at an aging temperature of 190℃. The level of the plateau toughness is affected by impurity content."
Aluminum-lithium alloys have been developed primarily to reduce the weight of aircraft and aerospace structures. More recently, they have been investigated for use in cryogenic applications.The major development work began in the 1970-1980, when aluminum producers accelerated the development of aluminum-lithium alloys as replacements for conventional airframe alloys. The lower-density aluminum-lithium alloys were expected to reduce the weight and improve the performance of aircraft.
Commercial aluminum-lithium alloys are targeted as advanced materials for aerospace technology primarily because of their low density, high specific modulus, and excellent fatigue and cryogenic toughness properties. The superior fatigue crack propagation resistance of aluminum-lithium alloys, in comparison with that of traditional 2xxx and 7xxx alloys, is primarily due to high levels of crack tip shielding, meandering crack paths, and the resultant roughness-induced crack closure. However, the fact that these alloys derive their superior properties from the above mechanisms has certain implications with respect to small crack and variable-amplitude behavior.
The principal disadvantages of peak-strength aluminum-lithium alloys are reduced ductility and fracture toughness in the short transverse direction, anisotropy of in-plane properties, the need for cold work to attain peak properties, and accelerated fatigue crack extension rates when cracks are micro structurally small. Commercial Aluminum-Lithium AlloysDevelopment of commercially available aluminum-lithium-base alloys was started by adding lithium to aluminum-copper, aluminum-magnesium, and aluminum-copper-magnesium alloys. These alloys were chosen to superimpose the precipitation-hardening characteristics of aluminum-copper-, aluminum-copper-magnesium-, and aluminum-magnesium-base precipitates to the hardening of lithium-containing precipitates. Proceeding in this manner, alloys 2020 (Al-Cu-Li-Cd), 01429 (Al-Mg-Li), 2090 (Al-Cu-Li), and 2091 and 8090 (Al-Cu-Mg-Li) evolved. Besides these registered alloys, other commercial aluminum-lithium alloys include Weldalite 049 and CP276.
Weldalite 049Chemical composition: Cu - 5.4, Li - 1.3, Ag - 0.4, Mg - 0.4, Zr - 0.14.Weldalite 049 shows high strength in variety of products and tempers. Its natural aging response is extremely strong with cold work (temper T3), and even stronger without cold work (T4); in fact, it has a stronger natural aging response than that of any other known aluminum alloy. Weldalite 049 undergoes reversion during the early stages of artificial aging and its ductility increases significantly up to 24%. Tensile strengths of 700 MPa have been attained in both T6 and 18 tempers produced in the laboratory.
Weldalite 049 has very good weldability. For example, it displays no discernable hot cracking in highly restrained weldment made by gas tungsten arc, gas metal arc and variable polarity plasma arc (VPPA) welding. Extremely high weldment strengths have been reported using conventional 2319 filler, and even higher weldment strengths have been obtained with the use of proprietary Weldalite filler.
Alloy 2090Chemical composition: Cu - 2.7, Li - 2.2, Ag - 0.4, Zr - 0.12.
Alloy 2090 was developed to be a high-strength alloy with 8% lower density and 10% higher elastic modulus than 7075-T6, a major high-strength alloy used in current aircraft structures. Alloy 2090 was registered with the Aluminum Association in 1984. A variety of tempers are being developed to offer useful combinations of strength, toughness, corrosion resistance, damage tolerance, and fabricability.
Because alloy 2090 and its tempers are relatively new and in different phases of registration and characterization, data concerning strength and toughness may be incomplete for some forms.
In general, the engineering characteristics of aluminum-lithium alloys are similar to those of the current 2xxx and 7xxx high-strength alloys used by the aerospace industry. However, some material features of the 2090 products vary somewhat from those of the conventional aluminum alloys and should be considered during the design and material design phase.
These distinct characteristics of 2090 include:
An in-plane anisotropy of tensile properties that is higher than in conventional alloys.
An elevated temperature exposure for the peak-aged tempers (T86, T81 and T83) that shows good stability within 10% of original properties.
Excellent fatigue crack growth behavior.
The need for cold work to achieve optimum properties. In this characteristic, 2090 is similar to 2219 and 2024.
Shape-dependent behavior for extrusions with very high strengths.
Alloy 2090 sheet and plate, and 2090-T86 extrusions have demonstrated excellent resistance to exfoliation corrosion in extensive seacoast exposure tests. The resistance of these alloys and tempers is superior to that of 7075-T6, which, in some product forms, can suffer very severe exfoliation during a two-year seacoast exposure.
The stress-corrosion cracking (SCC) resistance of 2090 is strongly influenced by artificial aging. Tempers that are under-aged, such as T84, may be more susceptible to SCC than the near-peak-aged T83, T81, and T86 tempers.
Alloy 2091Chemical composition: Cu - 2.1, Li - 2.0, Zr - 0.10.
Alloy 2091 was developed to be a damage-tolerant alloy with 8% lower density and 1% higher modulus than 2024-T3, a major high-toughness damage-tolerant alloy currently used for most aircraft structures. Alloy 2091 is also suitable for use in secondary structures where high strength is not critical.
Alloy 2091 has been registered with the Aluminum Association. A variety of tempers are being developed to offer useful combinations of strength, corrosion resistance, damage tolerance, and fabricability. The microstructure of 2091 varies according to product thickness and producer; in general, gages above 3.5 mm have an unrecrystallized microstructure, and lighter gages feature an elongated recrystallized grain structure.
In general, the behavior of 2091 is similar to that of other 2xxx and 7xxx alloys. Material characteristics that have been cause for concern in other aluminum-lithium alloys are of less concern in 2091. Alloy 2091 depends less on cold work to attain its properties than does 2024. The properties of 2091 after elevated-temperature (up to 125℃) exposure are relatively stable in that changes in properties during the lifetime of a component are acceptable for most commercial applications.
The exfoliation resistance of 2091-T84, like that of 2024, varies depending on the microstructure of the product and its quench rate. The more unrecrystallized the structure, the more even the exfoliation attack. However, the exfoliation resistance of 2091 is generally comparable to that of similar gages of 2024-T3.
The microstructural relationship for stress-corrosion cracking in sheet products is the converse of that for exfoliation. As the microstructure becomes more fibrous, the SCC threshold increases. For thicker unrecrystallized structures and thinner elongated recrystallized structures, it is possible to attain an SCC threshold of 240 MPa, which is quite good compared to that of 2024-T3. For thinner products, the threshold varies by gage and producer; it may be as low as 50 to 60% of the yield strength or as high as 75% of the yield strength.
Although fatigue testing on 2091 has been done by a number of labs, producers, and users, the results have been difficult to interpret. The results for 2091 have been superior to those for 2024, roughly equivalent to those for 2024, or inferior to those for 2024. In general, the consensus is that under controlled and similar circumstances, the fatigue properties of 2091-T84 are sufficient to allow it to be used as a substitute for 2024.
Alloy 8090Chemical composition: Li - 2.45, Zr - 0.12, Cu - 1.3, Mg - 0.95.
Alloy 8090 was developed to be a damage-tolerant medium-strength alloy with about 10% lower density and 11% higher modulus than 2024 and 2014, two commonly used aluminum alloys. Its use is aimed at applications where damage tolerance and the lowest possible density are critical. The alloy is available as sheet, plate, extrusions, and forgings and it can also be used for welded applications.
The chemical composition of 8090 has been registered with the Aluminum Association. A variety of tempers have been developed that offer useful combinations of strength, corrosion resistance, damage tolerance, and fabricability.
Because alloy 8090 and its tempers and product forms are relatively new and unregistered, property data are incomplete. The medium-strength products of alloy 8090 are aged to near-peak strength and show small changes in properties after elevated-temperature exposure. The very underaged (damage-tolerant) products will undergo additional aging upon exposure to elevated temperatures.
Changes in strength and toughness at cryogenic temperatures are more pronounced in 8090 than in conventional aluminum alloys: 8090 has a substantially higher strength and toughness at cryogenic temperatures.
The improving quality of commercially available aluminum-lithium alloys such as 8090 has resulted in significant improvements in short-transverse ductility and, consequently, short-transverse tensile strength. Research on the short-transverse fracture toughness of 8090 has shown that the property reaches a minimum plateau at an aging temperature of 190℃. The level of the plateau toughness is affected by impurity content."
No comments:
Post a Comment