冷却方式对8090铝锂合金搅拌摩擦加工区组织和硬度的影响

Effect of Cooling Mode on Microstructure and Hardness of 8090 Al Li Alloy Friction Stirring Zone

8090铝锂合金作为第二代铝锂合金,因质量轻,强度高,切削性能好,广泛用于航天航空领域的各种结构件。但铸造缺陷、第二相及晶粒粗大造成的力学性能恶化严重制约其实际应用。搅拌摩擦加工(FSP)是消除铸造缺陷、细化第二相及晶粒的有效技术之一。为探究FSP过程中冷却方式与晶粒细化及力学性能的内在联系,系统分析了冷却工艺对加工区成型、晶粒细化、显微硬度的影响。结果表明,在空冷的冷却条件下搅拌摩擦加工区域的显微硬度值最高,其他控冷冷却条件下,虽然晶粒细化的效果更好,但硬度值反而更小。

8090 aluminum lithium alloy,as the second generation aluminum lithium alloy,is widely used in various structural parts in aerospace field due to its light weight,high strength and good cutting performance.However,the deterioration of mechanical properties caused by casting defects,second phase and coarse grains seriously restricts its practical application.Friction stir processing(FSP)is one of the effective technologies to eliminate casting defects and refine the second phase and grains.In order to explore the internal relationship between cooling mode,grain refinement and mechanical properties in FSP process,the influence of cooling process on forming,grain refinement and microhardness of processing area was systematically analyzed.The results show that the microhardness of the friction stir zone is the highest under the air cooling condition,and the microhardness is smaller under other controlled cooling conditions,although the grain refinement effect is better.