Evolution of recrystallization and recrystallization texture in continuous-cast AA 3015 aluminum alloy
- PDF / 1,551,485 Bytes
- 20 Pages / 612 x 792 pts (letter) Page_size
- 67 Downloads / 222 Views
NTRODUCTION
TWIN-BELT continuous-cast (CC) processing of aluminum alloy sheets has recently gained extensive attention because of its high productivity and low conversion cost. In the CC processing, the molten metal is poured between two rotating steel belts to produce a cast slab, which is immediately fed into three consecutive hot-rolling mills, forming hot-band products. Due to different processing routes, there are distinct differences in microstructure and texture between the CC and direct-chill (DC) cast hot bands, which affect the evolution of microstructure and texture during subsequent processing and, hence, the formability of aluminum alloy sheets.[1–4] Therefore, relevant adjustment of processing parameters and strict control of microstructure and texture are necessary to improve the formability of CC aluminum alloy sheets. Recrystallization texture has long been a subject of research by metallurgists, since it is one of the main factors responsible for the anisotropy of properties of final sheet products. The recrystallization textures of most aluminum alloys are dominated by the cube orientation, with strong scatter about the rolling direction (RD) toward the Goss orientation. However, annealing of deformed supersaturated AA 3xxx series aluminum alloys usually results in different recrystallization textures due to the effect of concurrent precipitation.[5,6] The effect of concurrent precipitation on recrystallization and recrystallization texture has been reported.[7–11] It was found that concurrent precipitation significantly retarded the recrystallization of the AA 3003 aluminum alloy.[7,8] The presence of large flat grains aligned with the RD in a supersaturated Al-1.3 pct Mn alloy was attributed W.C. LIU, Senior Research Associate, and J.G. MORRIS, Professor of Metallurgical Engineering, are with the Department of Chemical and Materials Engineering, Light Metals Research Laboratories, University of Kentucky, Lexington, KY 40506. Manuscript submitted October 19, 2004. METALLURGICAL AND MATERIALS TRANSACTIONS A
to preferred nucleation of precipitation on large and lowangle grain boundaries.[9] Several articles have focused on the evolution of recrystallization texture during concurrent precipitation.[5,6,10] It was found that concurrent precipitation resulted in relatively strong P {011}455 and normal direction (ND)–rotated cube {001}310 textures in commercial Al-Mn-Mg[5] and Al-Mn[6] alloys. According to Engler and co-workers,[12,13] the enhanced P and ND-rotated cube textures originated from particle-stimulated nucleation of recrystallization. These orientations were a result of microgrowth selection, taking place in the deformation zone around the largest particles. The CC hot bands retain a large amount of alloying elements in solid solution due to the rapid cooling rate of the CC slab. A very strong P component has been observed in recrystallization textures of directly cold-rolled hot bands of CC AA 3004 and AA 3015 aluminum alloys.[14,15] However, the mechanism responsible for the formatio
Data Loading...
