1100-O (annealed) commercially pure aluminium, Kaiser Aluminum Tube & Pipe Alloy 1100 Technical Data (Rev. 05/06), typical properties; specific heat from Hydro EN AW-1050A (99.5% Al) extruded-products datasheet (10/2018).
Cleveland-Cliffs / AK Steel ARMCO Pure Iron Product Data Bulletin (07/2022): Table 1 typical physical properties, Table 2 typical mechanical properties after SRA/recrystallization anneal.
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is Aluminum 1100-O stronger than Iron?
Iron is stronger: its yield strength is 186 MPa against 35 MPa for Aluminum 1100-O (5.31x).
Which is lighter, Aluminum 1100-O or Iron?
Aluminum 1100-O is lighter: 2,710 kg/m³ against 7,860 kg/m³ for Iron.
Which is stiffer, Aluminum 1100-O or Iron?
Iron is stiffer: Young's modulus 207 GPa against 69 GPa for Aluminum 1100-O, so the same part in Iron deflects less under the same load.
Which is lighter for the same job, Aluminum 1100-O or Iron?
For the same stiffness or strength: Aluminum 1100-O is lighter for a stiff beam (bending), stiff panel or plate, strong panel or plate; Iron is lighter for a stiff rod or tie (tension), strong rod or tie, strong beam.
Part that must be
Aluminum 1100-O
Iron
Stiff rod or tie (tension)
3% heavier
lighter
Stiff beam (bending)
lighter
1.67x heavier
Stiff panel or plate
lighter
2.01x heavier
Strong rod or tie
1.83x heavier
lighter
Strong beam
5% heavier
lighter
Strong panel or plate
lighter
26% heavier
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, Aluminum 1100-O or Iron?
Aluminum 1100-O conducts heat better: 222 W/m·K against 73.2 W/m·K for Iron.
Which expands less with temperature?
Iron expands less: 13.7 µm/m·K against 23.6 µm/m·K for Aluminum 1100-O.