Hisaki Watari
Tokyo Denki University, Japan
Title: Hot forging of high-Aluminum content Magnesium alloys by using a servo press
Biography
Biography: Hisaki Watari
Abstract
This paper deals with an innovative hot-forging process of high-tensile-strength magnesium alloy materials that contains relatively high aluminum contents. By applying a servo press machine, a novel hot-forging process was performed with development of high-strength magnesium alloys. Firstly, friction properties and isothermal deformation resistance during hot forming (350℃ and 400℃) of Mg-Al-Ca-Mn series magnesium alloy (AXM4303 alloy) were investigated by ring-compression tests. In ring-compression tests, friction coefficients between dies and magnesium alloys are obtained using graphite, PTFE, and an oil lubricant. A novel lubricant that could prevent sticking between dies and material was developed by hot-forging experiments.
Secondary, high-tensile-strength magnesium alloys containing 9 to 12% aluminum, such as AZ91, AZ101, AZ111, and AZ121 have been made by twin-roll casting. A new experiment was performed for hot forging of high-strength magnesium alloys with high aluminum content was performed. From the results, using magnesium alloys with high aluminum content yielded less compressive deformation resistance than AXM403. It was also demonstrated that hot forging of magnesium alloys with high aluminum content produces small magnesium crystals (about 6 micrometers) and crystallized substances. The effects of the dynamic recrystallization on the microstructures of products formed at two different temperatures (300℃ and 350℃) seem to differ. Forging at 350℃ improved mechanical properties and yielded the best formability.
