Effect of Lubricant and Operation Temperature on the Metallurgical Property of AM60 Magnesium Alloy in ECAP Process

Abstract

In this study, the effect of the lubricant type and operating temperature on the process of equal channel angular pressing (ECAP) for magnesium alloy AM60 was investigated. For this purpose, designed experiments were conducted in a rounded cavity die with a channel angle of 90° at three different operating temperatures using two lubricants including graphite and molybdenum disulfide. Then, the apparent qualities, microhardness, microstructure of the samples, and variation in the process force were analyzed. Findings revealed that using the molybdenum disulfide as a lubricant at high temperature reduces damage to the workpiece and the process force. However, the ECAP process increases the hardness of the processed samples and the hardness is almost the same in different modes of lubrication. Moreover, at lower temperatures, the hardness of the samples is higher. The microstructure of the samples demonstrated that molybdenum disulfide lubricant leads to finer grain size and a higher level of alignment than lubrication using graphite. At higher temperatures, dynamic recrystallization occurs during deformation, leading to the formation of ultrafine equiaxed grains in some regions of the microstructure.