Abstract
On the Mechanical Properties and Corrosion Resistance of Mg-Mn-Al Alloys.
Influences of manganese and aluminium on the mechanical properties of Mg-Mn-Al alloys were investigated. Tensile strength, elongation and impact resistance are improved to some extent with addition of manganese up to 2%.
Effects of aluminium on the mechanical properties of these alloys are far more marked than manganese. The tensile strength increases with aluminium up to 6%, The elongation, reduction of arca, impact resistance decrease rapidly as aluminium increases.
The following experiments were made on the heat treatments of these alloys, in which aluminium plays an important role. After quenching and tempering. alloys of these series show a marked increase of hardness when the aluminium content is more than 8%. In the case of alloys, whose aluminium content is less than 6% the increase of hardness due to the heat treatment is not remarkable. In any alloys, the maximum hardness is obtained by tempering at 230.
Corrosion of alloys in water and in NaCl solution was also investigated. Manganese addition above 0.3% makes a remarkable improvement on the corrosion resistance. As to the content of manganese, it was found that 1% Mn in the cast state and 1.5% Mn in the heat-treated condition, show the maximum corrosion resistance. Influence of aluminium on the corrosion resistance in water is different from that in salt solution. In water aluminium has a beneficial effect, while in salt solution, the alloys of 6% Al are more corrodible than others.
