Effect of Zn and Mn Additions on the Wear Resistance of Cast Alloy Mg – 5% Al – 1% Si

Resumo

The effect of additions of Zn and Mn (from 0.5 to 4%) on the microstructure of alloy Mg – 5% Al – 1% Si is studied by the methods of x-ray diffractometry and light and scanning electron microscopy. The strength parameters are determined in tensile and wear tests. It is shown that particles of Mg₂Si precipitate in the matrix and particles of Mg₁₇Al₁₂ precipitate on grain boundaries upon the introduction of low contents of Zn and Mn. Phases MgZn and Al₆Mn precipitate at a high content of the additions. An optimum concentration of Zn and Mn is chosen for raising the wear resistance of alloy Mg – 5% Al – 1% Si.