喷射沉积2195铝锂合金轧制板材晶粒组织及性能控制研究

Grain structure and mechanical property control study of spray deposited 2195 Al-Li alloy

摘要:

研究了喷射沉积制备2195铝锂合金锭坯挤压板坯经不同终轧温度热轧至6 mm厚度板材，以及经不同中间退火后再冷轧至6 mm厚度板材固溶后的晶粒组织。结果表明，终轧温度290?C时，热轧板固溶后表层为粗大再结晶晶粒，而中心层为细长纤维状晶粒；终轧温度降低至220?C时，虽然表层再结晶晶粒尺寸减小，但中心层转变为尺寸粗大的长条状再结晶晶粒。板材中尺寸1 ?m以上的富Cu第二相粒子数量随中间退火（空冷）温度的增加（从330?C提高至450?C）而增加；冷轧固溶后表层等轴状再结晶晶粒尺寸增加，而中心层晶粒逐渐由粗大长条状再结晶晶粒转变为细小等轴状再结晶晶粒。适当温度中间退火、随炉冷却并冷轧、固溶后表层和中心层全部为细小等轴状再结晶晶粒。优化中间退火后的冷轧板材T8时效态强度最高，而终轧温度220?C的热轧板材T8时效态强度最低。

Abstract:

A spray deposited 2195 Al-Li alloy ingot was extruded into plates. Some of the extruded plates were hot rolled down to the thickness of 6 mm with different finish rolling temperature, and others were cold-rolled down to the thickness of 6mm after different intermediate annealing. The surface layer of the plate with finish rolling temperature 290°C consists of coarse recrystallized grains, but the center layer cosnsits of non-recrystallized fine fibrous grains. As the finish rolling temperature is lowered to 220°C, the size of the recrystallized grain in the surface layer is decreased, but grains in the center layer are transferred to coarse elongated recystallized grains. As the intermediate annealing temperature was elevated from 330°C to 450°C, the number density of Cu-rich secondary phase particles with size larger than 1 mm increases, the recrystallized grain in the surface layer of the cold-rolled plate after solutionization coarsenes, and the center layer grain were transferred to small equi-axed recrystallized grains from coarse elongated recrystallized grains. After approporiate intermediate annealing followed by furnace cooling, the cold-rolled plate through thickness after solutionization developed into fine recrystallized grains. After a same T8 aging, the strength of the cold-rolled plates are higher than that of the hot-rolled plates, and that of the plate with a finish rolling temperature of 220°C is the lowest.