Effect of Cooling Rate on Microstructure, Mechanical and Wear Properties of Mg-2Zn and Mg-2Zn-1Mn Alloys

In this study, the wear characteristics of Mg-2Zn and Mg2Zn-1Mn alloys in both dry and corrosive conditions, as well as their mechanical properties dependent on cooling rate, were examined. It has been determined that MgZn, Mg2Zn3 and MgZn2 phases are formed together with the alpha-Mg main matrix in the microstructure of the alloys. The highest tensile strength (188.6 MPa) was observed in section B of Mg-2Zn alloy. With this, section A of the Mg-2Zn-1Mn alloy showed the lowest wear value (0.00144 mm3/N.m) following dry wear. However, under corrosive wear conditions, the lowest wear rate (0.0008 mm3/N.m) was exhibited at B section in Mg-2Zn-1Mn alloy. In the SEM images of the abrasive tips used in the wear tests, it was determined that the scratches occurred along the wear direction, and as a result of the EDX analysis, alloying elements were transferred from the alloys to the abrasive tip. Dans cette etude, on a examine les caracteristiques d'usure des alliages Mg-2Zn et Mg-2Zn-1Mn dans des conditions seches et corrosives, ainsi que leurs proprietes mecaniques dependantes de la vitesse de refroidissement. On a determine que les phases MgZn, Mg2Zn3 et MgZN2 se forment ensemble avec la matrice principale Mg-alpha dans la microstructure des alliages. Les sections C des deux alliages montraient les valeurs de durete maximales, qui resultaient de la vitesse de refroidissement. Cependant, on a observe la resistance a la traction la plus elevee (188.6 MPa) dans la section B de l'alliage Mg-2Zn. Avec cela, on a observe la limite d'elasticite la plus elevee (69.7 MPa) dans la section A de l'alliage Mg-2Zn-1Mn. En meme temps, la section A de l'alliage Mg-2Zn-1Mn montrait la valeur d'usure la plus faible (0.00144 mm3/N center dot m) apres usure par voie seche. Cependant, dans des conditions d'usure corrosives, la section B de l'alliage Mg-2Zn-1Mn exhibait le taux d'usure le plus faible (0.0008 mm3/N center dot m). Dans les images du MEB des pointes abrasives utilisees lors des essais d'usure, on a determine que les rayures se produisaient dans le sens de l'usure et, a la suite de l'analyse EDX, les elements d'alliage etaient transferes des alliages vers la pointe abrasive.