Tensile strength

Tensile strength is a measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. 

The tensile strength of a material is the maximum amount of tensile stress that it can take before failure, for example breaking.

There are three typical definitions of tensile strength:

 Yield strength - The stress a material can withstand without permanent deformation. This is not a sharply defined point. Yield strength is the stress which will cause a permanent deformation of 0.2% of the original dimension.

 Ultimate strength - The maximum stress a material can withstand.

 Breaking strength - The stress coordinate on the stress-strain curve at the point of rupture.

Typical tensile strengths
Some typical tensile strengths of some materials:
+Typical tensile strengths of some materials Material  Yield strength (MPa)  Ultimate strength (MPa)  Density (g/cm³) Structural steel ASTM A36 steel               250  400  7.8 Steel, API 5L X65 (Fikret Mert Veral)       448  531  7.8 Steel, high strength alloy ASTM A514       690  760  7.8 Maraging_Steel, Grade 350  2400  2500  8.1 Steel Wire                                                7.8 Steel, Piano wire                       c. 2000         7.8 High density polyethylene (HDPE)        26-33   37   0.95  Polypropylene                           12-43   19.7-80   0.91  Stainless steel AISI 302 - Cold-rolled  520  860  8.03; Cast iron 4.5% C, ASTM A-48              130 (??)   200  7.3; Titanium Alloy (6% Al, 4% V)            830  900  4.51  Aluminum Alloy 2014-T6                    400  455  2.7 Copper 99.9% Cu                              70  220  8.92 Cupronickel 10% Ni, 1.6% Fe, 1% Mn, balance Cu  130  350  8.94 Brass                                            250    Tungsten                                      1510  19.25 Glass (St Gobain "R")                   4400 (3600 in composite)     2.53 Bamboo                                  142  265  .4 Marble                                  N/A  15    Concrete                                N/A  3    Carbon Fiber                            N/A  5650  1.75 Spider silk                             1150 (??)  1200    Silkworm silk                           500       Kevlar                                  3620     1.44 Vectran                                    2850-3340    Pine Wood (parallel to grain)          40    Bone (limb)                                130     Nylon, type 6/6  45  75  1.15 Rubber  -  15    Boron  N/A  3100  2.46 Silicon, monocrystalline (m-Si)  N/A  7000  2.33 Sapphire (Al2O3)  N/A  1900  3.9-4.1 Carbon nanotube (see note below)  N/A  62000  1.34 

Note: Multiwalled carbon nanotubes have the highest tensile strength of any material yet measured, with labs producing them at a tensile strength of 63 GPa, still well below their theoretical limit of 300 GPa.  However, as of 2004, no macroscopic object constructed of carbon nanotubes has had a tensile strength remotely approaching this figure, or substantially exceeding that of high-strength materials like Kevlar.

Note: many of the values depend on manufacturing process and purity/composition.

 Elements in the annealed state  Young's Modulus (GPa)  Proof or yield stress (MPa)  Ultimate strength (MPa) Aluminium  70  15-20  40-50 Copper  130  33  210 Gold  79    100 Iron  211  80-100  350 Lead  16     12 Nickel  170  14-35  140-195 Silicon  107  5000-9000    Silver  83     170 Tantalum  186  180  200 Tin  47  9-14  15-200 Titanium  120  100-225  240-370 Tungsten  411  550  550-620 Zinc (wrought)  105     110-200
(Source: A.M. Howatson, P.G. Lund and J.D. Todd, "Engineering Tables and Data" p41)

 Related pages 
Tension (mechanics)
Tensile stress
Deformation

 Other websites 
January 2003 sci.physics thread on water tensile strength and trees
Theory re the discrepancy in static vs dynamic measurements of water's tensile strength

Category:Materials science