Forgeability of AZ31B magnesium
alloy in warm forging
alloy in warm forging
(1. National Die and Mold CAD Engineering Research Center,
Shanghai Jiaotong University, Shanghai 200030, China;
2. Division of Mechanical Science, School of Engineering Science,
Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531, Japan)
Shanghai Jiaotong University, Shanghai 200030, China;
2. Division of Mechanical Science, School of Engineering Science,
Osaka University, Machikaneyama, Toyonaka, Osaka 560-8531, Japan)
Abstract: To understand the forming behaviour of magnesium alloys, the upsetting test of Mg alloys at evaluated temperature was conducted. It is found that Mg alloys are brittle at temperatures below 200℃. When temperature is higher than 400℃, Mg alloy is not suitable for forging because of heavy oxidation. Mg alloy shows an excellent workability at temperatures from 250 to 400℃. Because in warm forging the flow stress decreases with increasing strain, which is so-called work softening, no appropriate material formulation is available for Mg alloys. For the evaluation of flow stress of Mg alloys in warm forging processes, a formula is derived by analyzing the stress data measured at various temperatures in upsetting test. It is demonstrated that the formula fits the flow stress obtained from experiment.
Key words: magnesium alloy; flow stress; warm forging; work softening; dynamic recrystallization