Abstract
By rapid quenching of Al-1∼5%Mn alloys from the liquid state, an equilibrium structure, a structure formed by movement of the eutectic point, an incompletely super-saturated solid solution and a completely solid solution were obtained successively with increase in solidification rate. Micro-Vickers hardness measurement, tensile test and thermal analysis were used to examine the relations between the mechanical properties and these structures. The result obtained were as follows:
(1) With increase in solidification rate (V) (or change of solidified structures), Micro-Vickers hardness (Hv), ultimate tensile strength (σB) and elongation (δ) rose according to the relation of Y=AV+B or Y=C (Y: σB, Hv, δ, V: solidification rate, A, B, C: constant).
(2) The ranges of solidification rate at which each structure was formed, were shown by a diagram for Al-1∼5%Mn alloys.
(3) The constitution diagrams to show the relations of average solidification rate—thickness distance and Mn content—thickness distance were obtained.
