摘要
Thepurpose of the present paper is to study the mechanical propertiesand microstructureof the twin-roll cast and cold rolled AA5083 aluminum alloy sheet in strain-hardened H321 temper. To reach this goal, first, a sound surface slab of 8.90 mm thick and 1260 mm wide was cast by a 15°; tilt back twin roll caster at a casting speed of 490 mm/min. After homogenization at 520 ℃, the product was cold rolled to two thicknesses of 6.30 mm and 3.85 mm with an intermediate annealing at 370 ℃ and final stabilization at 180 ℃. Opticalmicroscopyand scanning electron microscopy （SEM） investigations of the as-cast state depicted the segregation of intermetallic particles mainly in grain boundaries which wasthe cause of grain removal observed in the fracture surface of tensile test samples. In addition, mechanical properties indicated an increase in total elongation after homogenization heat treatment dueto the elimination of the grain boundary segregations. Finally, it was observed that the properties of the 3.85 mmthick sheet were consistent with the H321 temper requirements according to ASTM B 290M standard due to applying sufficient cold reduction during cold rolling stage.
研究双辊铸轧和冷轧AA5083铝合金在H321应变硬化态下的显微组织和力学性能。通过15°倾斜后双辊铸轧机在490 mm/min铸造速度下制备厚8.90 mm、宽1260 mm厚板,板材表面完好。经520°C均匀化处理后,材料冷轧至6.30 mm和3.85 mm两种厚度的板材,并在370°C进行中间退火和180°C进行稳定化退火。光学显微镜和扫描电子显微镜研究表明金属间化合物颗粒主要聚集在晶界处,这也是拉伸断口中晶粒剥离的原因。另外,力学性能研究表明,经过均匀化处理后,晶界偏聚消除,合金的伸长率得到提高。由于在冷轧阶段得到足够大的压下量,3.85 mm厚板的性能符合ASTM B 290M标准的H321态性能。
