Formability investigation of 6061-T6 aluminum alloy sheet at elevated temperatures

Abstract Aluminum alloy sheets are widely used in different industries that the main reason is the high strength to weight ratio of these sheets. Among these sheets, the 6061-aluminum alloy (AA 6061) is more useable in automotive and aircraft industries, because of its high strength and more formability properties which have rather than most aluminum alloy sheets. Although AA 6061 sheet has more formability compare to most other aluminum alloy sheets, still it has low formability at room temperature which is one of its drawbacks. Therefore, in the present study, the formability of AA 6061-T6 sheets with thickness of 2 mm is investigated at different temperatures in the range of room temperature (RT) to 300℃. For this purpose, the experimental tests of forming limit diagram (FLD) are done at different temperatures by using the non-isothermal Nakajima standard die based on the ISO 12004-2 standard. The FLD tests are done with no lubrication in the sheet and punch contact at different temperatures. The results indicated that the FLD level and formability increased by temperature increase from RT to 100℃ and then decreased by temperature increase from 200℃ to 300℃. Results showed that happening of adhesive wear between the punch and the sheet surface is the main factor that restricted the material flow and deformation of sheet when the temperature is more than 100℃. The higher temperature which is used in the forming process, the stronger adhesive wear will happen.