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Domain: matweb.com

Stories and comments across the archive that link to matweb.com.

Comments · 13

  1. Re:a magnet? by georgewilliamherbert · · Score: 1 · on How To Tell If It's Really Titanium

    A poor volume to strength ratio?

    http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTP642

    Yield strength of 160,000 PSI and ultimate tensile strength of 170,000 PSI for that temper condition of Ti-6Al-4V, and there are better Titanium alloys out there.

    Yes, some of the really high strength maraging steels get better than twice that strength. But their use is even more restricted than Titanium is, because they're exotic to work and require the aging process after fabrication to attain the high strength. Few steels with more than about 150,000 PSI strength are in wide use. A vast majority of steels used widely have ultimate tensile strength less than 100,000 PSI. The exceptions are mostly T-1 / A514 for structural steel and 4130, 4140, and 4340 for machinery and aircraft parts.

  2. Not just strength and scratch resistance by TTK+Ciar · · Score: 2, Informative · on Insights Into the Future of the Laptop

    There's also the entirely different matter of stiffness (rigidity) and its relationship to mass. Steel, Aluminum, and Titanium are all plenty strong for building a laptop, but because their densities are dramatically different, a given mass of each translates to different thicknesses, which becomes the dominating factor in determining the plate's stiffness.

    The stiffness of a plate is approximately proportional to the cube of the plate's thickness multiplied by the material-specific flexural modulus. Most steel alloys have a flexural modulus of 205GPa, while cheap construction-grade Aluminum (alloy 6063, temper grade 6) has a modulus of only 69GPa. So a given thickness of steel is stiffer than the same thickness of aluminum, but steel is three times more dense than aluminum. This means that for the same mass budget, you can get an aluminum plate three times as thick. The cube of this ratio of thickness is 27, which when multiplied by the aluminum's modulus gives you an overall stiffness nine times greater than that of steel. This higher rigidity is highly desirable in products such as laptops, which you do not want to have flexing under the user's hands, or in the owner's backpack. The casing could have plenty of strength (ie, not break), but fail to protect the internal components from damage due to insufficient rigidity.

    An annealed high-strength titanium alloy (Titanium Ti-8Al-1Mo-1V) is only 55% as dense as most steels, is as strong and resilient as hardened steel (about 50% stronger than mild steels like the kind your car and laptop are made from), and has a modulus of 121GPa, betwixt that of steel and aluminum 6063-t6. So for a given mass budget, a plate of this titanium alloy would be about 1.8 times thicker, and 3.4 times more rigid, than a steel plate, but only 0.38 times as rigid as the aluminum 6063-t6 plate.

    I am thinking the main draw of titanium for laptops is probably scratch resistance (some titanium alloys are much more scratch-resistant than both steel and aluminum), which I guess would be a big draw for some customers. Personally I'd rather want the tougher aluminum laptop. (Better heat dissipation too, and probably somewhat cheaper, though the material costs of a laptop are a small fraction of its actual cost.) It's not like the aluminum laptop would be that much bulkier. 1.5mm steel is more than enough strength for such a product (your car's body is probably made from 1.5mm steel), and a triple thickness of this of aluminum would be only 4.5mm -- about 1/6th of an inch. I could totally live with that.

    -- TTK

  3. Polyethylene by chroma · · Score: 4, Interesting · on Fly To Mars In A Plastic Ship
    Polyethylene is one of the most commonly used plastics in the world, and is found in plastic grocery bags, cutting boards, milk jugs, disposable cups, and about a million other things. It's very stretchy, and thus is unlikely to break. It's tough, so that when it gets a hole or crack, the structure keeps its integrity. That's why I use it for armor on my fighting robots.

    According to MatWeb, Ultra High Molecular Weight Polyethylene (UHMW-PE) has an ultimate tensile strength of about 40 MPa, while 7075 alloy aluminum has an ultimate tensile strength of 524 MPa . The article claims that this new PE-derived material has a tensile strength 3x that of aluminum. I find a 40x improvement in tensile strength a bit tough to believe.

  4. Polyethylene by chroma · · Score: 4, Interesting · on Fly To Mars In A Plastic Ship
    Polyethylene is one of the most commonly used plastics in the world, and is found in plastic grocery bags, cutting boards, milk jugs, disposable cups, and about a million other things. It's very stretchy, and thus is unlikely to break. It's tough, so that when it gets a hole or crack, the structure keeps its integrity. That's why I use it for armor on my fighting robots.

    According to MatWeb, Ultra High Molecular Weight Polyethylene (UHMW-PE) has an ultimate tensile strength of about 40 MPa, while 7075 alloy aluminum has an ultimate tensile strength of 524 MPa . The article claims that this new PE-derived material has a tensile strength 3x that of aluminum. I find a 40x improvement in tensile strength a bit tough to believe.

  5. Polyethylene by chroma · · Score: 4, Interesting · on Fly To Mars In A Plastic Ship
    Polyethylene is one of the most commonly used plastics in the world, and is found in plastic grocery bags, cutting boards, milk jugs, disposable cups, and about a million other things. It's very stretchy, and thus is unlikely to break. It's tough, so that when it gets a hole or crack, the structure keeps its integrity. That's why I use it for armor on my fighting robots.

    According to MatWeb, Ultra High Molecular Weight Polyethylene (UHMW-PE) has an ultimate tensile strength of about 40 MPa, while 7075 alloy aluminum has an ultimate tensile strength of 524 MPa . The article claims that this new PE-derived material has a tensile strength 3x that of aluminum. I find a 40x improvement in tensile strength a bit tough to believe.

  6. 100 GPa in perspective by iamlucky13 · · Score: 2, Informative · on Nanotubes Start to Show their Promise
    The article stated the goal was 100 GPa (gigapascals...a measure of stress) tensile strength. The parent mentions the highest measured strength to date comes from a single-walled nanotube that bore 63 GPa (double-walled will theoretically hold more). To give you a comparison, I've pulled ultimate tensile strengths of common materials from matweb.com (note these are in MPa, not GPa, so the goal is 100,000 MPa)
    • Molded Nylon - 75 MPa
    • Plain carbon steel - 450 MPa
    • 4130 Cromoly steel - 1110 MPa
    • Dupont Kevlar 49 - 3620 MPa
    • Carbon Fiber - 4000 MPa (approx)
    As you can see, carbon fiber is about 4% as strong as the target, which tells you two things: First, nanotubes kick butt. Second, this elevator is not right around the corner. Sure they're getting good at making individual fibers, but the weave will not carry the same stress as the individual fibers, and we have to find a way to work around that.
  7. Physical properties look good... by Handpaper · · Score: 1 · on Sanyo Develops Corn-Based Biodegradeable CD

    According to data from Michigan State University and Matweb, tensile strength (it shouldn't fly apart) and Young's modulus (it shouldn't stretch too much) are comparable to materials currently used.

  8. Diamond also conducts heat VERY well... by CTho9305 · · Score: 1 · on The Diamond Age

    Diamond conducts heat about 5x better than copper. Maybe one day crazy overclockers can have diamond waterblocks or heatsinks cooling their diamond-wafer processors :).

  9. Diamond also conducts heat VERY well... by CTho9305 · · Score: 1 · on The Diamond Age

    Diamond conducts heat about 5x better than copper. Maybe one day crazy overclockers can have diamond waterblocks or heatsinks cooling their diamond-wafer processors :).

  10. Titanium Material Properties by kurthr · · Score: 3 · on Titanium As Cheap As Aluminum?
    Just so it's clear though, Titanium has some good points. Manufacturers seem to be able to build bikes out of it fairly easily. It's fatigue properties are significantly better than most any other material, especially at high temperature (discounting the single crystals like Ni & Si). Aluminum's fatigue strength is basically awful... try bending it a couple of times. Furthermore, Ti is rarely used as a pure metal (except for some marine and medical). Much like Aluminum, it occurs in common alloys like 6-4 (6% Al 4% Vanadium) and in alpha and beta anneal forms, which can have pretty different properties.

    See the extensive data for your selves:
    http://www.matweb.com/GetIndex2.asp
    MaterialType Fatigue(MPa)Density(g/cc)Melting(C)
    Al/6061 60 2.7 582
    Ti/11/6/4,720C 1000 5.06 1573
    Co/Cr/Ni Coldworked 500 8.3 1427
    Silicon /100/ 120 2.31414


    Aluminum has good points too... like it's got really high thermal/electrical conduction, and you can injection mold it. The latter is pretty cool, and happens because its high temp viscocity falls at high pressure. And interestingly if you go to small enough length scales like the TI micro-mirrors where you lengths are near the grain size of Aluminum the reliability goes way up.
    http://www.dlp.com/dlp/resources/whitepapers/mem s/dplmems/1intro.asp
  11. Titanium Material Properties by kurthr · · Score: 3 · on Titanium As Cheap As Aluminum?
    Just so it's clear though, Titanium has some good points. Manufacturers seem to be able to build bikes out of it fairly easily. It's fatigue properties are significantly better than most any other material, especially at high temperature (discounting the single crystals like Ni & Si). Aluminum's fatigue strength is basically awful... try bending it a couple of times. Furthermore, Ti is rarely used as a pure metal (except for some marine and medical). Much like Aluminum, it occurs in common alloys like 6-4 (6% Al 4% Vanadium) and in alpha and beta anneal forms, which can have pretty different properties.

    See the extensive data for your selves:
    http://www.matweb.com/GetIndex2.asp
    MaterialType Fatigue(MPa)Density(g/cc)Melting(C)
    Al/6061 60 2.7 582
    Ti/11/6/4,720C 1000 5.06 1573
    Co/Cr/Ni Coldworked 500 8.3 1427
    Silicon /100/ 120 2.31414


    Aluminum has good points too... like it's got really high thermal/electrical conduction, and you can injection mold it. The latter is pretty cool, and happens because its high temp viscocity falls at high pressure. And interestingly if you go to small enough length scales like the TI micro-mirrors where you lengths are near the grain size of Aluminum the reliability goes way up.
    http://www.dlp.com/dlp/resources/whitepapers/mem s/dplmems/1intro.asp
  12. Titanium Material Properties by kurthr · · Score: 3 · on Titanium As Cheap As Aluminum?
    Just so it's clear though, Titanium has some good points. Manufacturers seem to be able to build bikes out of it fairly easily. It's fatigue properties are significantly better than most any other material, especially at high temperature (discounting the single crystals like Ni & Si). Aluminum's fatigue strength is basically awful... try bending it a couple of times. Furthermore, Ti is rarely used as a pure metal (except for some marine and medical). Much like Aluminum, it occurs in common alloys like 6-4 (6% Al 4% Vanadium) and in alpha and beta anneal forms, which can have pretty different properties.

    See the extensive data for your selves:
    http://www.matweb.com/GetIndex2.asp
    MaterialType Fatigue(MPa)Density(g/cc)Melting(C)
    Al/6061 60 2.7 582
    Ti/11/6/4,720C 1000 5.06 1573
    Co/Cr/Ni Coldworked 500 8.3 1427
    Silicon /100/ 120 2.31414


    Aluminum has good points too... like it's got really high thermal/electrical conduction, and you can injection mold it. The latter is pretty cool, and happens because its high temp viscocity falls at high pressure. And interestingly if you go to small enough length scales like the TI micro-mirrors where you lengths are near the grain size of Aluminum the reliability goes way up.
    http://www.dlp.com/dlp/resources/whitepapers/mem s/dplmems/1intro.asp
  13. Titanium Material Properties by kurthr · · Score: 3 · on Titanium As Cheap As Aluminum?
    Just so it's clear though, Titanium has some good points. Manufacturers seem to be able to build bikes out of it fairly easily. It's fatigue properties are significantly better than most any other material, especially at high temperature (discounting the single crystals like Ni & Si). Aluminum's fatigue strength is basically awful... try bending it a couple of times. Furthermore, Ti is rarely used as a pure metal (except for some marine and medical). Much like Aluminum, it occurs in common alloys like 6-4 (6% Al 4% Vanadium) and in alpha and beta anneal forms, which can have pretty different properties.

    See the extensive data for your selves:
    http://www.matweb.com/GetIndex2.asp
    MaterialType Fatigue(MPa)Density(g/cc)Melting(C)
    Al/6061 60 2.7 582
    Ti/11/6/4,720C 1000 5.06 1573
    Co/Cr/Ni Coldworked 500 8.3 1427
    Silicon /100/ 120 2.31414


    Aluminum has good points too... like it's got really high thermal/electrical conduction, and you can injection mold it. The latter is pretty cool, and happens because its high temp viscocity falls at high pressure. And interestingly if you go to small enough length scales like the TI micro-mirrors where you lengths are near the grain size of Aluminum the reliability goes way up.
    http://www.dlp.com/dlp/resources/whitepapers/mem s/dplmems/1intro.asp