Effect of Rolling Temperature on Room Temperature Formability and Texture Formation of Mg-3 mass％Al-1 mass％Sn Alloy Sheet

Abstract

E ff ect of rolling temperature on room temperature formability and texture formation of Mg – 3mass ％ Al – 1mass ％ Sn ( AT31 ) alloy sheet was investigated, and compared with the results of Mg – 3mass ％ Al – 1mass ％ Zn ( AZ31 ) alloy sheet. When the rolling temperature was set to a high temperature ( 798K ) , AT31 alloy showed almost the same basal texture intensity as AZ31 alloy rolled at the same condition. When the rolling temperature was set to a low temperature ( 723K ) , AT31 alloy showed lower basal texture intensity than AZ31 alloy rolled at the same condition. As a result of Erichsen test, when the rolling temperature was set to 798K, AT31 alloy exhibited excellent Erichsen value more than 8.8mm, which corresponded to AZ31 alloy rolled at the same condition. On the other hand, when the rolling temperature was set to 723K, AT31 alloy exhibited higher Erichsen value ( 6.7mm ) than that of AZ31 alloy ( 4.5mm ) . The variations in Erichsen values with di ff erences in alloy composition and rolling temperature were closely related to the variations in basal texture intensity. Recrystallization behavior of AT31 alloy during the initial stage of the fi nal annealing was investigated. It is found that recrystallization mainly occurred at grain boundaries, and grains with more random orientation were recrystallized, when the rolling temperature was set to 798K. Mechanisms of recrystallization and random texture formation were almost the same with those of AZ31 alloy. The reason why AT31 alloy rolled at 723K exhibited more random texture than AZ31 rolled at the same condition is that grains with more random orientation were recrystallized at grain boundaries during the fi nal annealing.