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New alloys have been discovered that are stronger and ligher than diamond. These alloys have an amorphous structure rather than the crystalline structure of conventional alloys. A crystaline alloy tends to be weak at the boundaries between crystals and this limits its strength. Amorphous alloys don't have these weaknesses and can be stronger.
Pure metals and alloys consisting of 2 or 3 different metals tend to be crystaline while alloys with 5 or more metals tend to be amorphous. The new superalloys are mixes of at least 5 different metals.
A material's strength is characterized by the "yield strength" and the quality is the ratio of the yield strength to the density. This is often referred to as the "strength to weight ratio".
Yield strength = Y (Pascals) Density = D (kg/meter3) Quality = Q = Y/D (Joules/kg)The strongest allyos are:
Yield strength Density Quality
(GPa) (g/cm3) (MJoule/kg)
Magnesium + Lithium .14 1.43 98
Magnesium + Y2O3 .31 1.76 177
Aluminum + Beryllium .41 2.27 181
Amorphous LiMgAlScTi 1.97 2.67 738
Diamond 1.6 3.5 457
Titanium + AlVCrMo 1.20 4.6 261
Amorphous AlCrFeCoNiTi 2.26 6.5 377
Steel + Cobalt, Nickel 2.07 8.6 241
Amorphous VNbMoTaW 1.22 12.3 99
Molybdenum+ Tungsten, Hafnium 1.8 14.3 126
The strongest pure metals are weaker than the strongest alloys.
Yield strength Density Quality
(GPa) (g/cm3) (MJoule/kg)
Magnesium .10 1.74 57
Beryllium .34 1.85 184
Aluminum .02 2.70 7
Titanium .22 4.51 49
Chromium .14 7.15 20
Iron .10 7.87 13
Cobalt .48 8.90 54
Molybdenum .25 10.28 24
Tungsten .95 19.25 49
Beryllium + Li → Doesn't exist. The atoms don't mix Beryllium + Al → Improves strength Magnesium + Li → Weaker and lighter than pure Mg. Lightest existing alloy Magnesium + Be → Only tiny amounts of beryllium can be added to magnesium Magnesium + Carbon tubes → Improves strength, with an optimal tube fraction of 1% Aluminum + Li,Mg,Be,Sc → Stronger and lighter than aluminum Titanium + Li,Mg,Sc → Stronger and lighter than titanium Steel + Cr,Mo → Stronger and more uncorrodable than steel. "Chromoly" Copper + Be → Stronger than beryllium and is unsparkable
Melting point (Celsius)
Tungsten 3422
Rhenium 3186
Osmium 3033
Tantalum 3017
Molybdenum 2623
Niobium 2477
Iridium 2446
Ruthenium 2334
Hafnium 2233
Technetium 2157
Rhodium 1964
Vanadium 1910
Chromium 1907
Most alloys weaken with increasing temperature except for a small subset called "superalloys" that strengthen with temperature, such as Ni3Al and Co3Al. This is called the "yield strength anomaly".
Nickel alloys in jet engines have a surface temperature of 1150 Celsius and a bulk temperature of 980 Celsius. This is the limiting element for jet engine performance. Half the mass of a jet engine is superalloy.
Current engines use Nickel superalloys and Cobalt superalloys are under development that will perform even better.
Yield strength in GPa as a function of Celsius temperature.
20 600 800 900 1000 1100 1200 1400 1600 1800 1900 Celsius
VNbMoTaW 1.22 .84 .82 .75 .66 .48 .4
AlMohNbTahTiZr 2.0 1.87 1.60 1.2 .74 .7 .25
Nickel superalloy 1.05 1.20 .90 .60 .38 .15
Tungsten .95 .42 .39 .34 .31 .28 .25 .10 .08 .04
Below 1100 Celsius AlMohNbTahTiZr has the best strength-to-mass ratio and above
this VNbMoTaW has the best ratio. Both alloys supersede nickel superalloy
and both outperform tungsten, the metal with the highest melting point.
Data:
Entropy, nickel superalloy
Yield strength (GPa)
Copper .27
Brass .41 30% zinc
Bronze .30 5% tin
Phosphor bronze .69 10% tin, .25% phosphorus
Copper + beryllium 1.2 2% beryllium, .3% cobalt
Copper + nickel + zinc .48 18% nickel, 17% zinc
Copper + nickel .40 10% nickel, 1.25% iron, .4% manganese
Copper + aluminum .17 8% aluminum
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Bells and cymbals are made from bell bronze, 4 parts copper and 1 part tin.
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Carbides are the hardest metallic materials.
10 Diamond 9.5 BN, B4C, B, TiB2, ReB2 9.25 TiC, SiC 9.0 Corundum, WC, TiN 8.5 Cr, TaC, Si3N4 8 Topaz, Cubic zirconia 7.5 Hardened steel, tungsten, emerald, spinel 7 Osmium, Rhenium, Vanadium, Quartz
Min Max
Valence compounds 1000 4000 carbides, borides, silicides
Intermetallic 650 1300
BCC lattice 300 700
FCC lattice 100 300
The deformation of a solid is characterized by shear strain, tensile strain, and bulk compression.
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Tensile strength relates to the strength of wires.
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Shear strength relates to the strength of beams and columns.
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Concrete and ceramics typically have much higher compressive strengths than tensile strengths. Composite materials, such as glass fiber epoxy matrix composite, tend to have higher tensile strengths than compressive strengths.
Primary Added Yield Break Stiff Strain Poi- Density Vick Elong Yield/ Melt metal metals (GPa) (GPa) (Gpa) sson (g/cm3) density (C) Magnesium Li .16 45 1.43 .098 Magnesium Y2O3 .312 .318 1.76 .177 Magnesium Tube .295 .39 49 1.83 .05 .161 Beryllium .345 .448 287 .0016 .032 1.85 .186 Aluminum Be40 .41 .46 185 2.27 .07 .181 Aluminum Mg Li .21 .35 75 .0047 2.51 Aluminum Cu Li .48 .53 2.59 .185 Aluminum Mg Sc .433 .503 2.64 .105 .164 LiMgAlScTi 1.97 2.67 5.8 .738 Titanium Be Al 3.91 Titanium Al6V4 .89 1.03 114 .33 4.43 .34 .14 1660 Titanium VCrMoAl 1.20 1.30 4.6 .08 .261 Vit 1 1.9 6.1 5.7 AlCoCrFeNiTih 2.26 3.14 6.5 .23 .377 Zirconium Liquid 1.52 1.52 93 6.57 .56 .018 .231 AlCoCrFeNiMo 2.76 7.1 .394 AlMohNbTahTiZr 2.0 2.37 7.4 .270 Inconel 718 8.19 Copper Be 1.2 1.48 130 .30 8.25 .145 866 CrFeNiV.5W 2.24 ~8.5 Iron Co Ni 2.07 2.38 8.6 .11 .241 Iron Cr Mo 9 .32 Nickel Cr 1.2 2.3 245 .32 8.65 6.6 TiZrNbHfTa .93 9.94 3.83 .5 TiVNbMoTaW 11.70 4.95 VNbMoTaW 12.36 NbMoTaW 13.75 Molybdenum W45Hf1 ~1.8 2.14 ~14.3 3.6 .126 Tungsten MoNiFe .62 .90 365 17.7 .10 .035 Yield: Yield modulus Break: Tensile strength (breaking point) Stiffness: Young's modulus Strain: Fractional strain at the breaking point Poisson: Poisson ratioMany properties of alloys are approximately equal to a linear sum of the properties of its constituent elements. This applies for density, stiffness modulus, and Poisson's ratio.
Many properties of alloys can be dramatically different from those of its constiuent elements. This applies for the yield modulus, the tensile breaking modulus, and the hardness.
For aluminum alloys, density = 2.71 - .01 Mg - .079 Li.
Magnesium strengthens when alloyed with aluminum, nickel, copper, and neodymium.
Data: TiVNbMoTaW AlTiNbMo½Ta½Zr Mg Be+Al Aluminum+Mg+Li Table Al+Be Mg + Li Mg alloys Elasticity Ti alloy Ti alloy Ti alloy textbook Liquidmetal Mg + tubes
Elasticity table Al Cu Li Al + tubes Mg + tubes W + Mo Al Mg Sc Fe + Co + Ni Li2MgSc2Ti3Al2 Entropy survey Entropy survey Entropy survey * CrFeNiV½W Entropy rev 2014 Nickel Chromium Copper textbook TiZrNbHfTa |
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