Materials Database

In majority of cases, trust specs given by the manufacturer or supplier over the specs in this database when they are given.

Steels

AR500 Steel

Type	Carbon Steel
Modulus of Elasticity	30,000 ksi
Poisson's Ratio	0.29
Density	0.29 lb/in^3
Ultimate Tensile Strength	225 ksi
Tensile Yield Strength	200 ksi
Brinell Hardness	450 HB
Rockwell Hardness	C48
Elongation at Break	12%
Familiar Sellers	McMaster Carr, MakeItRingTargets, Alro Steel, SendCutSend

Material Description:

• High strength, abrasian resistant steel used in body armor and shooting targets
• Hardened steel is very difficult to machine, is typically only used for Waterjet parts
• Typically used for weapons and wedges due to it's high strength, toughness, and relatively high hardness
• Used more commonly as armor in higher weight classes
• Anecdotal experience from builders says that AR500 typically bends before it fractures
• Will rust over time when wet or exposed to moist air

Aluminum Alloys

Aluminum 6061-T6

Type	Aluminum Alloy
Modulus of Elasticity	10,000 ksi
Shear Modulus	3800 ksi
Poisson's Ratio	0.33
Density	0.0984 lb/in^3
Ultimate Tensile Strength	45 ksi
Tensile Yield Strength	39 ksi
Fracture Toughness (T-L dir)	26.4 ksi-in½
Brinell Hardness	93 HB
Rockwell Hardness	B52
Elongation at Break	10%
Machinability (Vs. 1112 Steel)	270%
Familiar Sellers	McMaster Carr, Midwest Steel Supply, SendCutSend

Material Description:

• Lightweight aluminum alloy that comes already pre-heat-treated T6 temper which gives it its strength
• Beware of tempers T4 and O which are weaker than 6061-T6
• Typically used for frame rails, plates, pulleys, and armor for some bots
• Tends to fail in bending before fracturing
• Tends to "ablate" and may take gashes when hit directly by weapons
• Easy to machine and relatively cheap

Aluminum 7075-T6

Type	Aluminum Alloy
Modulus of Elasticity	10,000 ksi
Shear Modulus	3800 ksi
Poisson's Ratio	0.32
Density	0.102 lb/in^3
Ultimate Tensile Strength	81 ksi
Tensile Yield Strength	69 ksi
Fracture Toughness (T-L dir)	22.8 ksi-in½
Brinell Hardness	150 HB
Rockwell Hardness	B87
Elongation at Break	7.9%
Machinability (Vs. 1112 Steel)	170%
Familiar Sellers	McMaster Carr, Midwest Steel Supply, SendCutSend

Material Description:

• Aerospace grade aluminum alloy which is much stronger and harder than 6061-T6
• Pre-heat-treated to T6 temper
• Past and anecdotal experience notes that it tends to fracture before it bends
• Some builders recommend avoiding using it as armor or for parts that take direct hits due to fracture risk
• Relatively easy to machine and is more expensive than 6061-T6

Titanium Alloys

Grade 5 Titanium (Ti-6Al-4V)

Type	Titanium Alloy
Modulus of Elasticity	16510 ksi
Shear Modulus	5800 ksi
Poisson's Ratio	0.32
Density	0.160 lb/in^3
Ultimate Tensile Strength	138-150 ksi
Tensile Yield Strength	128-140 ksi
Fracture Toughness (Annealed Plate)	67.9 ksi-in½
Brinell Hardness	310 HB
Rockwell Hardness	C34
Elongation at Break	6.7%
Machinability (Vs. 1112 Steel)	20%
Familiar Sellers	McMaster Carr, SendCutSend, TMS Titanium

Material Description:

• Very high strength and high toughness metal alloy
• Denser than aluminum but less dense than steel
• Typically sold and used in its annealed state for high toughness
• Typically used for armor, structural plates, sometimes weapons, it's pretty versatile material overall
• Very expensive
• Very difficult to machine or drill due to work hardening properties
• In some cases, outsourcing to SendCutSend might be financial preferable to buying Ti stock so discuss with your PM

Sources

• AR500 Steel: SendCutSend, McMaster Carr, Steel Warehouse
• Al 6061-T6: SendCutSend, Matweb, Machining Doctor
• Al 7075-T6: SendCutSend, Matweb, Machining Doctor
• Ti-6Al-4V: SendCutSend, Matweb, Machining Doctor