Alloys

Copper
Orichalcum (gold + copper)
Gold

Alloy of gold, silver, and copper


Strongest alloys
                   Yield    Density   Yield/Density
                  strength  (g/cm3)    (GJoule/kg)
                   (GPa)
Magnesium  + Li        .14     1.43      .098
Magnesium  + Y2O3      .31     1.76      .177
Aluminum   + Be        .41     2.27      .181
LiMgAlScTi            1.97     2.67      .738
Titanium   + AlVCrMo  1.20     4.6       .261
AlCrFeCoNiTi          2.26     6.5       .377
AlCrFeCoNiMo          2.76     7.1       .394
Steel      + Co Ni    2.07     8.6       .241
VNbMoTaW              1.22    12.3       .099
Molybdenum + W Hf     1.8     14.3       .126

Sapphire               .4      3.98      .101
Diamond               1.6      3.5       .457
Magnesium              .10     1.74      .057
Beryllium              .34     1.85
Aluminum               .020    2.70
Titanium               .22     4.51
Chromium               .14     7.15
Iron                   .10     7.87
Cobalt                 .48     8.90
Nickel                 .19     8.91
Copper                 .12     8.96
Molybdenum             .25    10.28
Tin                    .014    7.26
Tungsten               .947   19.25
Rhenium                .290   21.02
Osmium                        22.59
Iridium                       22.56
Alloys can be vastly stronger than their constituent elements. Alloys such as "TiScAlLiMg" are "high entropy alloys", which are a mix of elements in approximately equal proportions.
For comparison, the table includes pure metals, diamond, and sapphire. Large synthetic sapphires and small synthetic diamonds can be constructed. The recently developed LiMgAlScTi alloy is the first metal to outpeform diamond.
Alloy types
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 cannot spark

Column buckling

If too much weight is placed on a column it buckles. Suppose a column is constructed with constant mass and varying density. The lower the density the wider and stronger the column.

Radius            =  R
Length            =  L
Density           =  D
Mass              =  M  =  π D L R2
Buckling constant =  C
Tensile modulus   =  K
Force             =  F  =  C K R4 L-2      Force requird to buckle the column
Quality           =  Q  =  F / M  =  K M D-2 L-4
The figure of merit for a material for columns is K D2. Balsa wood has a density of .16 g/cm3 and outperforms the strongest alloys.
                   Yield    Density  Yield/Density  Yield/Density2
                  strength  (g/cm3)    (GJoule m3/kg2)
                   (GPa)
Balsa                  .006     .16      .037    .234
Bamboo                 .0079    .35      .023    .064
Magnesium  + Li        .14     1.43      .098    .068
Magnesium  + Y2O3      .31     1.76      .177    .100
Aluminum   + Be        .41     2.27      .181    .080
LiMgAlScTi            1.97     2.67      .738    .276
Titanium   + AlVCrMo  1.20     4.6       .261    .057
AlCrFeCoNiTi          2.26     6.5       .377    .053
AlCrFeCoNiMo          2.76     7.1       .394    .055

High-temperature metals (refractory metals)
          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

High-temperature superalloys

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 supercede nickel superalloy and both outperform tungsten, the metal with the highest melting point. Data:   
Entropy, nickel superalloy
Copper alloys
                  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

Bells and cymbals

Bells and cymbals are made from bell bronze, 4 parts copper and 1 part tin.


Mohs hardness

Carbide

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

Full list of alloys
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 ratio
Many 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


Vickers hardness
                       Min   Max

Valence compounds     1000  4000     carbides, borides, silicides
Intermetallic          650  1300
BCC lattice            300   700
FCC lattice            100   300