How do non-heat treatable aluminium alloys typically increase their strength?

Non-heat treatable aluminum alloys primarily increase their strength through strain hardening, also known as work hardening. This process involves deforming the material mechanically, typically through methods such as rolling, drawing, or extrusion. As the material undergoes plastic deformation, dislocations within the metal structure increase, which impedes the movement of other dislocations. This results in a higher strength and improved hardness of the alloy.

Adding alloying elements typically serves to enhance various properties of aluminum but does not involve the strengthening mechanisms used in non-heat treatable alloys. Heat treatment and quenching are also processes that are specific to heat-treatable aluminum alloys and are not applicable to non-heat treatable varieties. Thus, the correct method for increasing strength in non-heat treatable aluminum alloys is strain hardening.