F. Abu-Farha, Penn State University/Erie, Erie, PA; L. Hector, General Motors R&D Center, Warren, MI; M. Nazzal, German-Jordanian University, Amman, Jordan
With the ever-growing interest in lightweight alloy sheets for potential applications in the transportation sector, the need for accurate forming limit diagrams (FLD’s) at higher-than-ambient temperatures is becoming a necessity, since these materials are typically formed at elevated temperatures. Unhappily, mechanical stretching tests, such as the ones according to the Marciniak and Nakazima methods, are generally limited to warm forming temperatures (~350 ºC). Pneumatic stretching, on the other hand, has the advantage of being applicable to much higher temperatures, in addition to eliminating possible friction influences. In this work, the latter approach is utilised to construct the forming limit curves for the AA5083 alloy at temperatures as high as 550 ºC. Such formability maps will be instrumental in understanding the material behaviour, and hence optimising actual superplastic and quick plastic forming practices.
